DUF / Duff & Phelps Corp - SEC-arkivering, Årsberetning, Fuldmagtserklæring

Duff & Phelps Corp
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SEC Filings
All companies that sell securities in the United States must register with the Securities and Exchange Commission (SEC) and file reports on a regular basis. These reports include company annual reports (10K, 10Q), news updates (8K), investor presentations (found in 8Ks), insider trades (form 4), ownership reports (13D, and 13G), and reports related to the specific securities sold, such as registration statements and prospectus. This page shows recent SEC filings related to Duff & Phelps Corp
SEC Filings (Chronological Order)
Denne side giver en komplet, kronologisk liste over SEC-arkiveringer, eksklusive ejerskabsregistreringer, som vi leverer andre steder.
February 13, 2014 SC 13G

DUF / Duff & Phelps Corp / BARROW HANLEY MEWHINNEY & STRAUSS LLC - SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* Duff & Phelps Corp. Cl A (Name of Issuer) Common Stock (Title of Class of Securities) 26433B107 (CUSIP Number) December 31, 2013 (Date of Event Which Requires Filing of this Statement) Check appropriate box to designate the rule pursuant to which this Sch

May 3, 2013 15-12B

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dakotaform15.htm - Generated by SEC Publisher for SEC Filing UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 15 CERTIFICATION AND NOTICE OF TERMINATION OF REGISTRATION UNDER SECTION 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR SUSPENSION OF DUTY TO FILE REPORTS UNDER SECTIONS 13 AND 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number 001-34518 DUFF

April 23, 2013 S-8 POS

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dakotas-8.htm - Generated by SEC Publisher for SEC Filing As filed with the Securities and Exchange Commission on April 23, 2013 Registration Statement No. 333-148144 Registration Statement No. 333-169380 Registration Statement No. 333-181880 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 Registration Statement No. 333-148144 Regi

April 23, 2013 10-K/A

Annual Report - 10-K/A FOR THE YEAR ENDED DECEMBER 31, 2012

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1) þ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the year ended December 31, 2012 OR ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-33693 DUFF & PHELP

April 23, 2013 EX-99.1

Private Investor Consortium Completes Acquisition of Duff & Phelps Corporation

dakotaex991.htm - Generated by SEC Publisher for SEC Filing Exhibit 99.1 Press Release Private Investor Consortium Completes Acquisition of Duff & Phelps Corporation New York, NY, April 23, 2013 — Duff & Phelps Corporation (“the Company”) today announced the completion of its acquisition by a consortium (“the Consortium”) comprising controlled affiliates of or funds managed by The Carlyle Group, S

April 23, 2013 POS AM

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forms-3posteffectiveamdt.htm - Generated by SEC Publisher for SEC Filing As filed with the Securities and Exchange Commission on April 23, 2013 Registration Statement No. 333-181132 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 Post-Effective Amendment No. 1 to Form S-3 Registration Statement No. 333-181132

April 23, 2013 S-8 POS

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dakotas-8.htm - Generated by SEC Publisher for SEC Filing As filed with the Securities and Exchange Commission on April 23, 2013 Registration Statement No. 333-148144 Registration Statement No. 333-169380 Registration Statement No. 333-181880 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 Registration Statement No. 333-148144 Regi

April 23, 2013 EX-3.2

ARTICLE I OFFICES ARTICLE II MEETINGS OF STOCKHOLDERS ARTICLE III DIRECTORS ARTICLE IV OFFICERS ARTICLE V MISCELLANEOUS ARTICLE VI AMENDMENTS

dakotaex32.htm - Generated by SEC Publisher for SEC Filing Exhibit 3.2 BY-LAWS OF DUFF & PHELPS CORPORATION ARTICLE I OFFICES SECTION 1. REGISTERED OFFICE ‑‑ The registered office of Duff & Phelps Corporation (the “Corporation”) shall be established and maintained at the office of 1209 Orange Street, Wilmington, Delaware 19801, County of New Castle, and Corporation Trust Company shall be the regis

April 23, 2013 8-K

Changes in Control of Registrant, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Material Modification to Rights of Security Holders, Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing, Financial Statements and Exhibits, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant, Completion of Acquisition or Disposition of Assets, Other Events -

dakota8k.htm - Generated by SEC Publisher for SEC Filing UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 23, 2013 DUFF & PHELPS CORPORATION (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559

April 23, 2013 EX-3.1

ARTICLE I ARTICLE II ARTICLE III ARTICLE IV ARTICLE V ARTICLE VI ARTICLE VII ARTICLE VIII ARTICLE IX

dakotaex31.htm - Generated by SEC Publisher for SEC Filing Exhibit 3.1 AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF DUFF & PHELPS CORPORATION ARTICLE I The name of the corporation (which is hereinafter referred to as the “Corporation”) is: Duff & Phelps Corporation. ARTICLE II The address of the Corporation’s registered office in the State of Delaware is 1209 Orange Street, Wilmington, Del

April 23, 2013 S-8 POS

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dakotas-8.htm - Generated by SEC Publisher for SEC Filing As filed with the Securities and Exchange Commission on April 23, 2013 Registration Statement No. 333-148144 Registration Statement No. 333-169380 Registration Statement No. 333-181880 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 Registration Statement No. 333-148144 Regi

April 23, 2013 EX-99.25

EX-99.25

NOTIFICATION OF THE REMOVAL FROM LISTING AND REGISTRATION OF THE STATED SECURITIES The New York Stock Exchange hereby notifies the SEC of its intention to remove the entire class of the stated securities from listing and registration on the Exchange at the opening of business on May 6, 2013, pursuant to the provisions of Rule 12d2-2 (a).

April 22, 2013 8-K

Submission of Matters to a Vote of Security Holders - FORM 8-K

Form 8-K UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 22, 2013 (April 22, 2013) DUFF & PHELPS CORPORATION (Exact name of Registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Employer Identification No.

April 10, 2013 SC 13G/A

DUF / Duff & Phelps Corp / FMR LLC Passive Investment

SCHEDULE 13G Amendment No. 2 DUFF & PHELPS CORP NEW Class A Common Stock Cusip #26433B107 Cusip #26433B107 Item 1: Reporting Person - FMR LLC Item 4: Delaware Item 5: 501 Item 6: 0 Item 7: 601 Item 8: 0 Item 9: 601 Item 11: 0.001% Item 12: HC Cusip #26433B107 Item 1: Reporting Person - Edward C. Johnson 3d Item 4: United States of America Item 5: 0 Item 6: 0 Item 7: 601 Item 8: 0 Item 9: 601 Item

April 8, 2013 DEFA14A

- DEFA14A

DEFA14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant x Filed by a Party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a6(e)(2)) ¨ Def

March 21, 2013 DEFM14A

- DEFM14A

DEFM14A Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

March 20, 2013 PRER14A

- PRER14A

PRER14A Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

March 20, 2013 LETTER

LETTER

March 20, 2013 Via E-mail Noah Gottdiener Chief Executive Officer Duff & Phelps Corporation 55 East 52 St.

March 20, 2013 DEF 14A

- DEF 14A

DEF 14A Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

March 11, 2013 CORRESP

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CORRESP 601 Lexington Avenue New York, New York 10022 (212) 446-6450 [email protected] (212) 446-4800 Facsimile: (212) 446-6460 www.kirkland.com March 11, 2013 Via EDGAR Transmission United States Securities and Exchange Commission Division of Corporate Finance 100 F Street, NE Washington, D.C. 20549 Attention: Ramin M. Olson Re: Duff & Phelps Corporation; PREM 14A; Filed February 6, 2

March 6, 2013 LETTER

LETTER

March 5, 2013 Via E-mail Noah Gottdiener Chief Executive Officer Duff & Phelps Corporation 55 East 52 St.

February 25, 2013 EX-99.1

DUFF & PHELPS REPORTS 2012 FOURTH QUARTER RESULTS, AND DECLARES QUARTERLY DIVIDEND

FOR IMMEDIATE RELEASE DUFF & PHELPS REPORTS 2012 FOURTH QUARTER RESULTS, AND DECLARES QUARTERLY DIVIDEND FOURTH QUARTER HIGHLIGHTS: • Quarterly revenue of $145.

February 25, 2013 10-K

Annual Report - 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K þ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the year ended December 31, 2012 OR ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact

February 25, 2013 EX-21.1

DUFF & PHELPS CORPORATION AND SUBSIDIARIES LIST OF SUBSIDIARIES AS OF DECEMBER 31, 2012 Corporate Name Jurisdiction of Incorporation CETERIS US, LLC Illinois D&P Canada Acquisition Corp Canada D&P European Holdings, LLC Delaware D&P International Hol

EXHIBIT 21.1 DUFF & PHELPS CORPORATION AND SUBSIDIARIES LIST OF SUBSIDIARIES AS OF DECEMBER 31, 2012 Corporate Name Jurisdiction of Incorporation CETERIS US, LLC Illinois D&P Canada Acquisition Corp Canada D&P European Holdings, LLC Delaware D&P International Holdings, LLC Delaware Duff & Phelps (H.K.) Holdings Limited Hong Kong SAR Duff & Phelps Acquisitions, LLC Delaware Duff & Phelps B.V. The N

February 25, 2013 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 25, 2013 (February 25, 2013) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of inc

February 20, 2013 SC 13G/A

DUF / Duff & Phelps Corp / EAGLE ASSET MANAGEMENT INC Passive Investment

February 19, 2013 Office of the Corporate Secretary Duff & Phelps Corp. 55 East 52nd Street New York, NY 10055 RE: Amended Schedule 13G Duff & Phelps Corp. As ofJanuary 31, 2013 Gentlemen: In accordance with Section 13(d)(5) of the Securities Exchange Act of 1934, attached please find a copy of Amended Schedule 13G for the above named company showing a change of beneficial ownership of 5% or more

February 14, 2013 SC 13G/A

DUF / Duff & Phelps Corp / FMR LLC Passive Investment

SCHEDULE 13G Amendment No. 1 DUFF & PHELPS CORP NEW Class A Common Stock Cusip #26433B107 Cusip #26433B107 Item 1: Reporting Person - FMR LLC Item 4: Delaware Item 5: 469 Item 6: 0 Item 7: 2,718,946 Item 8: 0 Item 9: 2,718,946 Item 11: 6.724% Item 12: HC Cusip #26433B107 Item 1: Reporting Person - Edward C. Johnson 3d Item 4: United States of America Item 5: 0 Item 6: 0 Item 7: 2,718,946 Item 8: 0

February 12, 2013 DEFA14A

- 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 12, 2013 (February 11, 2013) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of inc

February 12, 2013 8-K

Financial Statements and Exhibits, Other Events - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 12, 2013 (February 11, 2013) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of inc

February 12, 2013 EX-99.1

Duff & Phelps Corporation Announces Expiration of the “Go-Shop” Period

EXHIBIT 99.1 Duff & Phelps Corporation Announces Expiration of the “Go-Shop” Period New York, NY, February 11, 2013 — Duff & Phelps Corporation (NYSE: DUF) (the “Company”), a leading independent financial advisory and investment banking firm, announced today that, following the expiration of the “go-shop” period provided for in its previously announced merger agreement with a Consortium comprising

February 12, 2013 EX-99.1

Duff & Phelps Corporation Announces Expiration of the “Go-Shop” Period

EXHIBIT 99.1 Duff & Phelps Corporation Announces Expiration of the “Go-Shop” Period New York, NY, February 11, 2013 — Duff & Phelps Corporation (NYSE: DUF) (the “Company”), a leading independent financial advisory and investment banking firm, announced today that, following the expiration of the “go-shop” period provided for in its previously announced merger agreement with a Consortium comprising

February 11, 2013 SC 13G

DUF / Duff & Phelps Corp / BARROW HANLEY MEWHINNEY & STRAUSS LLC - SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* Duff & Phelps Corporation (Name of Issuer) Common Stock (Title of Class of Securities) 26433B107 (CUSIP Number) December 31, 2012 (Date of Event Which Requires Filing of this Statement) Check appropriate box to designate the rule pursuant to which this Sc

February 6, 2013 PREM14A

- PRELIMINARY MERGER PROXY STATEMENT

Preliminary Merger Proxy Statement Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

February 5, 2013 SC 13G/A

DUF / Duff & Phelps Corp / TimesSquare Capital Management, LLC - AMENDMENT NO. 3 TO SCHEDULE 13G Passive Investment

AMENDMENT NO. 3 TO SCHEDULE 13G SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 3)1 Duff & Phelps Corporation (Name of Issuer) Common Stock, $0.01 par value (Title of Class of Securities) 26433B107 (CUSIP Number) December 31, 2012 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to desi

January 29, 2013 SC 13G/A

DUF / Duff & Phelps Corp / EAGLE ASSET MANAGEMENT INC Passive Investment

January 29, 2013 Securities and Exchange Commission 450 Fifth Street NW Washington, DC 20549 RE: Amended Schedule 13G Duff & Phelps Corp.

December 31, 2012 EX-99.1

Duff & Phelps Agrees to be Acquired by Private Investor Consortium

Exhibit 99.1 Duff & Phelps Agrees to be Acquired by Private Investor Consortium - Transaction Valued at Approximately $665.5M; Stockholders to Receive $15.55 per Share - - Consortium Includes Entities or Funds Managed by The Carlyle Group, Stone Point Capital, Pictet & Cie and Edmond de Rothschild Group - New York, NY – December 30, 2012 – Duff & Phelps Corporation (NYSE: DUF) (“the Company”), a l

December 31, 2012 EX-2.1

Agreement and Plan of Merger Duff & Phelps Corporation, Duff & Phelps Acquisitions, LLC, Dakota Holding Corporation, Dakota Acquisition I, Inc. Dakota Acquisition II, LLC Dated as of December 30, 2012 TABLE OF CONTENTS Page ARTICLE I The Mergers; Clo

Exhibit 2.1 ========================================================================================== Agreement and Plan of Merger Among Duff & Phelps Corporation, Duff & Phelps Acquisitions, LLC, Dakota Holding Corporation, Dakota Acquisition I, Inc. and Dakota Acquisition II, LLC Dated as of December 30, 2012 ========================================================================== TABLE OF CO

December 31, 2012 EX-2.1

Agreement and Plan of Merger Duff & Phelps Corporation, Duff & Phelps Acquisitions, LLC, Dakota Holding Corporation, Dakota Acquisition I, Inc. Dakota Acquisition II, LLC Dated as of December 30, 2012 TABLE OF CONTENTS Page ARTICLE I The Mergers; Clo

Exhibit 2.1 ========================================================================================== Agreement and Plan of Merger Among Duff & Phelps Corporation, Duff & Phelps Acquisitions, LLC, Dakota Holding Corporation, Dakota Acquisition I, Inc. and Dakota Acquisition II, LLC Dated as of December 30, 2012 ========================================================================== TABLE OF CO

December 31, 2012 EX-99.2

Note to Duff & Phelps Employees by Chief Executive Officer, dated December 30, 2012

Exhibit 99.2 Note to Duff & Phelps Employees by Chief Executive Officer, dated December 30, 2012 Dear Colleagues, Today, we announced a plan to transition Duff & Phelps from public to private ownership. Specifically, a consortium of financial sponsors—including funds or entities managed by The Carlyle Group, Stone Point Capital, Pictet & Cie and Edmond de Rothschild Group—have agreed to acquire Du

December 31, 2012 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Other Events - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) December 31, 2012 (December 30, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of inc

December 31, 2012 DEFA14A

- 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) December 31, 2012 (December 30, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of inc

December 31, 2012 EX-99.2

Note to Duff & Phelps Employees by Chief Executive Officer, dated December 30, 2012

Exhibit 99.2 Note to Duff & Phelps Employees by Chief Executive Officer, dated December 30, 2012 Dear Colleagues, Today, we announced a plan to transition Duff & Phelps from public to private ownership. Specifically, a consortium of financial sponsors—including funds or entities managed by The Carlyle Group, Stone Point Capital, Pictet & Cie and Edmond de Rothschild Group—have agreed to acquire Du

December 31, 2012 EX-99.1

Duff & Phelps Agrees to be Acquired by Private Investor Consortium

Exhibit 99.1 Duff & Phelps Agrees to be Acquired by Private Investor Consortium - Transaction Valued at Approximately $665.5M; Stockholders to Receive $15.55 per Share - - Consortium Includes Entities or Funds Managed by The Carlyle Group, Stone Point Capital, Pictet & Cie and Edmond de Rothschild Group - New York, NY – December 30, 2012 – Duff & Phelps Corporation (NYSE: DUF) (“the Company”), a l

December 31, 2012 424B7

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated May 29, 2012) Registration No. 333-181132 Duff & Phelps Corporation Class A Common Stock

424B7 1 a2012-12x31prospectussuppl.htm 424B7 PROSPECTUS SUPPLEMENT Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated May 29, 2012) Registration No. 333-181132 Duff & Phelps Corporation Class A Common Stock This prospectus supplement supplements and amends the prospectus dated May 29, 2012 relating, in part, to the resale from time to time of up to 7,987,920 shares of our

December 5, 2012 8-K/A

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers - 8-K/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) December 5, 2012 (December 3, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other j

November 14, 2012 424B7

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated May 29, 2012) Registration No. 333-181132 Duff & Phelps Corporation Class A Common Stock

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated May 29, 2012) Registration No.

October 29, 2012 EX-99.1

Duff & Phelps Appoints Norman S. Matthews to Board of Directors

EXHIBIT 99.1 Duff & Phelps Appoints Norman S. Matthews to Board of Directors NEW YORK—October 25, 2012—Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking firm, announced today that Norman S. Matthews has joined the company's board of directors. Matthews is the former president of Federated Department Stores, Inc. Noah Gottdiener, chief executive

October 29, 2012 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 29, 2012 (October 24, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incor

October 26, 2012 10-Q

Quarterly Report - 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended September 30, 2012 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact name of registr

October 25, 2012 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 25, 2012 (October 25, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incor

October 25, 2012 EX-99.1

DUFF & PHELPS REPORTS 2012 THIRD QUARTER RESULTS, AND DECLARES QUARTERLY DIVIDEND

FOR IMMEDIATE RELEASE DUFF & PHELPS REPORTS 2012 THIRD QUARTER RESULTS, AND DECLARES QUARTERLY DIVIDEND HIGHLIGHTS: • Quarterly revenue of $111.

October 22, 2012 EX-99.1

Duff & Phelps Acquires Ceteris

Duff & Phelps Acquires Ceteris Duff & Phelps Strengthens and Expands Global Transfer Pricing Capabilities by Acquiring CETERIS® NEW YORK, October 18, 2012 - Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking firm, today announced that it has acquired CETERIS®, a global economic consulting firm providing transfer pricing expertise along with strategic economic analysis and tax valuation services.

October 22, 2012 8-K

Unregistered Sales of Equity Securities, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 22, 2012 (October 18, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incor

October 10, 2012 SC 13G/A

DUF / Duff & Phelps Corp / EAGLE ASSET MANAGEMENT INC Passive Investment

October 10, 2012 Securities and Exchange Commission 450 Fifth Street NW Washington, DC 20549 RE: Amended Schedule 13G Duff & Phelps Corp.

August 14, 2012 424B7

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated May 29, 2012) Registration No. 333-181132 Duff & Phelps Corporation Class A Common Stock

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated May 29, 2012) Registration No.

August 13, 2012 EX-10.1

FIFTH AMENDMENT TO CREDIT AGREEMENT

EXHIBIT 10.1 FIFTH AMENDMENT TO CREDIT AGREEMENT This FIFTH AMENDMENT to Credit Agreement (this “Amendment”) is entered into as of August 10, 2012, among DUFF & PHELPS, LLC, a Delaware limited liability company (the “Borrower”), DUFF & PHELPS ACQUISITIONS, LLC (“Holdings”), CHANIN CAPITAL PARTNERS LLC (“Chanin”), and RASH & ASSOCIATES, L.P. (“Rash” and together with Holdings and Chanin, each a “Gu

August 13, 2012 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits - ITEM 1.01 AND ITEM 9.01

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 13, 2012 (August 10, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorpo

August 13, 2012 SC 13D/A

DUF / Duff & Phelps Corp / VESTAR CAPITAL PARTNERS IV LP - AMENDMENT NO. 5 TO SCHEDULE 13D Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13D Under the Securities Exchange Act of 1934 (Amendment No. 5)* Duff & Phelps Corporation (Name of Issuer) Class A Common Stock, par value $0.01 per share (Title of Class of Securities) 26433B107 (CUSIP Number) Sander Levy Vestar Capital Partners IV, L.P. 245 Park Avenue, 41st Floor New York, New York 10167 (212) 351

August 9, 2012 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits - ENTRY INTO A DEFINITIVE MATERIAL AGREEMENT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 9, 2012 (August 6, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorpora

August 9, 2012 EX-1.1

Duff & Phelps Corporation A Common Stock, par value $0.01 Underwriting Agreement

Duff & Phelps Corporation A Common Stock, par value $0.01 Underwriting Agreement August 6, 2012 Goldman, Sachs & Co. 200 West Street New York, New York 10282-2198 As representative of the several Underwriters named in Schedule I hereto Ladies and Gentlemen: The stockholders named in Schedule II hereto (the “Selling Stockholders”) of Duff & Phelps Corporation, a Delaware corporation (the “Company”)

August 8, 2012 424B5

3,000,000 Shares Duff & Phelps Corporation Class A Common Stock Goldman, Sachs & Co. ABOUT THIS PROSPECTUS SUPPLEMENT CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS PROSPECTUS SUPPLEMENT SUMMARY THE OFFERING USE OF PROCEEDS PRICE RANGE OF CLAS

Filed Pursuant to Rule 424(b)(5) Registration No. 333-181132 Prospectus Supplement (To Prospectus dated May 29, 2012) 3,000,000 Shares Duff & Phelps Corporation Class A Common Stock Our Class A common stock is listed on the New York Stock Exchange (the “NYSE”) under the symbol “DUF.” The last reported sale price of our Class A common stock on August 6, 2012 was $14.72 per share. Investing in our C

August 6, 2012 FWP

DUFF & PHELPS ANNOUNCES COMMON STOCK OFFERING OF 3,000,000 SHARES BY SELLING STOCKHOLDERS

Filed Pursuant to Rule 433 Registration No. 333-181132 DUFF & PHELPS DUFF & PHELPS ANNOUNCES COMMON STOCK OFFERING OF 3,000,000 SHARES BY SELLING STOCKHOLDERS NEW YORK, August 6, 2012 – Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking firm, today announced the commencement of an underwritten public offering of 3,000,000 shares of its common sto

July 25, 2012 10-Q

Quarterly Report - QUARTERLY REPORT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended June 30, 2012 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact name of registrant a

July 24, 2012 EX-99.1

DUFF & PHELPS REPORTS 2012 SECOND QUARTER RESULTS, AND DECLARES QUARTERLY DIVIDEND

FOR IMMEDIATE RELEASE DUFF & PHELPS REPORTS 2012 SECOND QUARTER RESULTS, AND DECLARES QUARTERLY DIVIDEND HIGHLIGHTS: • Quarterly revenues of $118.

July 24, 2012 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition - CURRENT REPORT ITEMS 2.02 AND 9.01

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) July 24, 2012 (July 24, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporati

June 5, 2012 S-8

- FORM S-8

As filed with the Securities and Exchange Commission on June 5, 2012 Registration No.

May 25, 2012 CORRESP

-

DUFF & PHELPS CORPORATION 55 East 52nd Street, 31st Floor New York, New York 10055 May 25, 2012 VIA EDGAR AND EMAIL Securities and Exchange Commission Division of Corporation Finance 100 F Street, NE Washington, D.

May 22, 2012 S-3/A

- AMENDMENT NO.1 TO FORM S-3

As filed with the Securities and Exchange Commission on May 22, 2012 Registration No.

May 22, 2012 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits - ITEM 5.02 COMPENSATORY ARRANGEMENTS OF CERTAIN OFFICERS

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 22, 2012 (May 18, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation

May 22, 2012 CORRESP

-

DUFF & PHELPS CORPORATION 55 East 52nd Street, 31st Floor New York, New York 10055 May 22, 2012 VIA EDGAR AND EMAIL Securities and Exchange Commission Division of Corporation Finance 100 F Street, NE Washington, D.

May 22, 2012 EX-10.1

Mr. Patrick Puzzuoli

Mr. Patrick Puzzuoli Duff & Phelps Corporation 55 E 52nd St., Fl. 31 New York, NY 10055 May 18, 2012 Dear Patrick: This letter agreement shall amend and restate in its entirety the letter agreement entered into between you and the Company which was effective March 7, 2011, pursuant to which you were appointed Executive Vice President and Chief Financial Officer of Duff & Phelps Corporation (togeth

May 16, 2012 424B7

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No. 333-162551 Duff & Phelps Corporation Class A Common Stock

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No.

May 15, 2012 LETTER

LETTER

May 14, 2012 Via Email Edward S. Forman, Esq. General Counsel Duff & Phelps Corporation 55 East 52 nd Street, 31 st Floor New York, New York 10055 Re: Duff & Phelps Corporation Registration Statement on Form S-3 Filed May 3, 2012 File No. 333-181132 Dear Mr. Forman: We have limited our review of your registration statement to the issue we have addressed in our comment below. In our comment, we ask

May 3, 2012 S-3

- FORM S-3

As filed with the Securities and Exchange Commission on May 3, 2012 Registration No.

May 3, 2012 EX-12.1

Computation of Ratio of Earnings to Fixed Charges(1)

Computation of Ratio of Earnings to Fixed Charges(1) Successor Predecessor Period from Period from Quarter Ended Quarter Ended Year Ended Year Ended Year Ended Year Ended October 4 to January 1 to March 31, March 31, December 31, December 31, December 31, December 31, December 31, October 3, 2012 2011 2011 2010 2009 2008 2007 2007 Income before income taxes $ 9,236 $ 9,555 $ 43,570 $ 42,849 $ 40,9

May 3, 2012 EX-25.1

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTE

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTEE PURSUANT TO SECTION 305(b)(2) || THE BANK OF NEW YORK MELLON (Exact name of trustee as specified in its charter) New York (Jurisdiction of incorpora

April 25, 2012 10-Q

Quarterly Report - QUARTERLY REPORT FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended March 31, 2012 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact name of registrant

April 24, 2012 EX-99.1

DUFF & PHELPS REPORTS 2012 FIRST QUARTER RESULTS AND DECLARES QUARTERLY DIVIDEND

FOR IMMEDIATE RELEASE DUFF & PHELPS REPORTS 2012 FIRST QUARTER RESULTS AND DECLARES QUARTERLY DIVIDEND HIGHLIGHTS: • Quarterly revenues of $108.

April 24, 2012 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) April 24, 2012 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commission

April 23, 2012 8-K/A

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers - ITEM 5.02 ELECTION OF DIRECTORS

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) April 23, 2012 (April 19, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other juris

April 23, 2012 8-K

Submission of Matters to a Vote of Security Holders - ITEM 5.07 SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) April 23, 2012 (April 19, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorpora

March 29, 2012 424B7

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No. 333-162551 Duff & Phelps Corporation Class A Common Stock

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No.

March 14, 2012 SC 13D/A

DUF / Duff & Phelps Corp / VESTAR CAPITAL PARTNERS IV LP - AMENDMENT NO. 4 TO SCHEDULE 13D Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13D Under the Securities Exchange Act of 1934 (Amendment No. 4)* Duff & Phelps Corporation (Name of Issuer) Class A Common Stock, par value $0.01 per share (Title of Class of Securities) 26433B107 (CUSIP Number) Sander Levy Vestar Capital Partners IV, L.P. 245 Park Avenue, 41st Floor New York, New York 10167 (212) 351

March 12, 2012 SC 13G/A

DUF / Duff & Phelps Corp / BlackRock Inc. Passive Investment

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No: 1) DUFF & PHELPS CORP - (Name of Issuer) Common Stock - (Title of Class of Securities) 26433B107 - (CUSIP Number) February 29, 2012 - (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is

March 12, 2012 SC 13D/A

DUF / Duff & Phelps Corp / VESTAR CAPITAL PARTNERS IV LP - AMENDMENT NO. 3 TO SCHEDULE 13D Activist Investment

SC 13D/A 1 d309118dsc13da.htm AMENDMENT NO. 3 TO SCHEDULE 13D UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13D Under the Securities Exchange Act of 1934 (Amendment No. 3)* Duff & Phelps Corporation (Name of Issuer) Class A Common Stock, par value $0.01 per share (Title of Class of Securities) 26433B107 (CUSIP Number) Sander Levy Vestar Capital Partners IV, L.P.

March 9, 2012 SC 13D/A

DUF / Duff & Phelps Corp / Lovell Minnick Partners Llc - SC 13D/A Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D/A Under the Securities Exchange Act of 1934 (Amendment No. 2) Duff & Phelps Corporation (Name of Issuer) Class A Common Stock, par value $0.01 per share (Title of Class of Securities) 26433B107 (CUSIP Number) Jennings J. Newcom Lovell Minnick Partners LLC Radnor Financial Center 150 N. Radnor Chester Road, Suite A

March 6, 2012 SC 13D/A

DUF / Duff & Phelps Corp / VESTAR CAPITAL PARTNERS IV LP - AMENDMENT NO. 2 TO SCHEDULE 13D Activist Investment

Amendment No. 2 to Schedule 13D UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13D Under the Securities Exchange Act of 1934 (Amendment No. 2)* Duff & Phelps Corporation (Name of Issuer) Class A Common Stock, par value $0.01 per share (Title of Class of Securities) 26433B107 (CUSIP Number) Sander Levy Vestar Capital Partners IV, L.P. 245 Park Avenue, 41st Floor Ne

March 5, 2012 DEF 14A

- PROXY STATEMENT PURSUANT TO SECTION 14(A)

DEF 14A 1 a2012proxydocument.htm PROXY STATEMENT PURSUANT TO SECTION 14(A) UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant þ Filed by a Party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential

March 2, 2012 EX-1.1

Duff & Phelps Corporation Class A Common Stock, par value $0.01 Underwriting Agreement

EXHIBIT 1.1 EXECUTION COPY Duff & Phelps Corporation Class A Common Stock, par value $0.01 Underwriting Agreement February 27, 2012 Goldman, Sachs & Co. 200 West Street New York, New York 10282-2198 As representative of the several Underwriters named in Schedule I hereto Ladies and Gentlemen: Duff & Phelps Corporation, a Delaware corporation (the “Company”), proposes, subject to the terms and cond

March 2, 2012 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) March 2, 2012 (February 27, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorpo

March 1, 2012 424B7

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No. 333-162551

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No.

March 1, 2012 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits - ITEM 5.02

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) March 1, 2012 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commission

March 1, 2012 EX-99.1

Duff & Phelps Appoints Gordon A. Paris to Board of Directors

EXHIBIT 99.1 Duff & Phelps Appoints Gordon A. Paris to Board of Directors New York, NY, March 1, 2012—Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking firm, announced today that Gordon A. Paris has joined the company's board of directors. Paris served as the interim president of MediaNews Group, Inc. from January 2011 to October 2011 and a boar

February 29, 2012 424B5

Prospectus - 424B5

Filed Pursuant to Rule 424(b)(5) Registration No. 333-162551 Prospectus Supplement (To Prospectus dated October 26, 2009) 4,500,000 Shares Duff & Phelps Corporation Class A Common Stock Our Class A common stock is listed on the New York Stock Exchange (the “NYSE”) under the symbol “DUF.” The last reported sale price of our Class A common stock on February 27, 2012 was $15.08 per share. Investing i

February 27, 2012 FWP

DUFF & PHELPS ANNOUNCES COMMON STOCK OFFERING OF 4,500,000 SHARES

Filed Pursuant to Rule 433 Registration No. 333-162551 DUFF & PHELPS ANNOUNCES COMMON STOCK OFFERING OF 4,500,000 SHARES NEW YORK, February 27, 2012 – Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking firm, today announced that it has commenced an underwritten public offering of 4,500,000 shares of its common stock. Duff & Phelps is offering 3,2

February 21, 2012 EX-21.1

DUFF & PHELPS CORPORATION AND SUBSIDIARIES LIST OF SUBSIDIARIES AS OF DECEMBER 31, 2011 Corporate Name Jurisdiction of Incorporation Chanin & Company, LLC California Chanin Advisors, LLC Delaware Chanin Capital Partners, LLC California D&P Canada Acq

EX-21.1 2 exhibit211listofsubsidiari.htm LIST OF SUBSIDIARIES EXHIBIT 21.1 DUFF & PHELPS CORPORATION AND SUBSIDIARIES LIST OF SUBSIDIARIES AS OF DECEMBER 31, 2011 Corporate Name Jurisdiction of Incorporation Chanin & Company, LLC California Chanin Advisors, LLC Delaware Chanin Capital Partners, LLC California D&P Canada Acquisition Corp Canada D&P International Holdings, LLC Delaware Duff & Phelps

February 21, 2012 10-K

Annual Report - ANNUAL REPORT ON FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K þ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the year ended December 31, 2011 OR ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact

February 15, 2012 EX-99.1

DUFF & PHELPS REPORTS 2011 FOURTH QUARTER AND FULL YEAR RESULTS, AND DECLARES QUARTERLY DIVIDEND

FOR IMMEDIATE RELEASE DUFF & PHELPS REPORTS 2011 FOURTH QUARTER AND FULL YEAR RESULTS, AND DECLARES QUARTERLY DIVIDEND FOURTH QUARTER HIGHLIGHTS: • Quarterly revenues of $124.

February 15, 2012 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 15, 2012 (February 15, 2012) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of inc

February 14, 2012 SC 13G

DUF / Duff & Phelps Corp / FMR LLC Passive Investment

SCHEDULE 13G Amendment No. 0 DUFF & PHELPS CORP NEW Class A Common Stock Cusip #26433B107 Cusip #26433B107 Item 1: Reporting Person - FMR LLC Item 4: Delaware Item 5: 1,122 Item 6: 0 Item 7: 2,249,345 Item 8: 0 Item 9: 2,249,345 Item 11: 7.400% Item 12: HC Cusip #26433B107 Item 1: Reporting Person - Edward C. Johnson 3d Item 4: United States of America Item 5: 0 Item 6: 0 Item 7: 2,249,345 Item 8:

February 10, 2012 SC 13G/A

DUF / Duff & Phelps Corp / Capital World Investors - SC 13G/A Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)* Duff & Phelps Corp (Name of Issuer) Class A Common Stock (Title of Class of Securities) 26433B107 (CUSIP Number) December 30, 2011 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which t

February 9, 2012 SC 13G

DUF / Duff & Phelps Corp / BlackRock Inc. Passive Investment

SECURITIES AND EXCHANGE COMMISSION Washington, D.C.20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No: ) DUFF & PHELPS CORP - (Name of Issuer) Common Stock - (Title of Class of Securities) 26433B107 - (CUSIP Number) December 30, 2011 - (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is f

February 8, 2012 SC 13G/A

DUF / Duff & Phelps Corp / TimesSquare Capital Management, LLC - SCHEDULE 13G AMENDMENT NO.2 Passive Investment

Schedule 13G Amendment No.2 SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)1 Duff & Phelps Corporation (Name of Issuer) Common Stock, $0.01 par value (Title of Class of Securities) 26433B107 (CUSIP Number) December 31, 2011 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designat

February 2, 2012 8-K

Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 2, 2012 DUFF & PHELPS CORPORATION (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commissi

January 26, 2012 SC 13G

DUF / Duff & Phelps Corp / Cortina Asset Management, LLC - DUF13G123111 Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1) DUFF & PHELPS CORPORATION - (Name of Issuer) Common Stock - (Title of Class of Securities) 26433B107 - (CUSIP Number) December 31, 2011 - (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to w

January 24, 2012 SC 13G/A

DUF / Duff & Phelps Corp / EAGLE ASSET MANAGEMENT INC Passive Investment

January 19,2012 Securities and Exchange Commission 450 Fifth Street NW Washington, DC 20549 RE: Schedule 13G Duff & Phelps Corp.

January 4, 2012 EX-99.1

Duff & Phelps Agrees to Acquire Pagemill Partners Addition of Silicon Valley-Based M&A Firm Enhances Global Technology Industry Expertise

EXHIBIT 99.1 Duff & Phelps Agrees to Acquire Pagemill Partners Addition of Silicon Valley-Based M&A Firm Enhances Global Technology Industry Expertise NEW YORK, December 19, 2011—Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking firm, today announced that it has entered into a definitive agreement to acquire Pagemill Partners, a Silicon Valley-b

January 4, 2012 EX-99.2

Duff & Phelps Completes Acquisition of Pagemill Partners

EXHIBIT 99.2 Duff & Phelps Completes Acquisition of Pagemill Partners NEW YORK, January 3, 2012—Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking firm, today announced that it has successfully completed the acquisition of Pagemill Partners, a Silicon Valley-based investment banking and valuation services firm. The acquisition, which will enhance

January 4, 2012 8-K

Unregistered Sales of Equity Securities, Financial Statements and Exhibits - ITEM 3.02 UNREGISTERED SALES OF EQUITY SECURITIES

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) January 4, 2012 (December 30, 2011) DUFF & PHELPS CORPORATION (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incor

December 12, 2011 EX-99.1

RSM Richter's Financial Restructuring Practice in Toronto Joins Duff & Phelps' Canadian Business

EXHIBIT 99.1 RSM Richter's Financial Restructuring Practice in Toronto Joins Duff & Phelps' Canadian Business NEW YORK, December 12, 2011?Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking services firm, today announced that RSM Richter's Financial Restructuring Practice in Toronto has joined Duff & Phelps' existing team in Canada. RSM Richter's

December 12, 2011 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) December 9, 2011 (December 12, 201

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) December 9, 2011 (December 12, 2011) DUFF & PHELPS CORPORATION (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of inco

November 10, 2011 424B7

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No. 333-162551 Duff & Phelps Corporation Class A Common Stock

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No.

November 1, 2011 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended September 30, 2011 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact name of registr

November 1, 2011 EX-99.1

DUFF & PHELPS REPORTS 2011 THIRD QUARTER RESULTS, AND DECLARES QUARTERLY DIVIDEND

EXHIBIT 99.1 FOR IMMEDIATE RELEASE DUFF & PHELPS REPORTS 2011 THIRD QUARTER RESULTS, AND DECLARES QUARTERLY DIVIDEND HIGHLIGHTS: ? Quarterly revenues of $94.4 million including reimbursable expenses (representing a $7.6 million or 8.7% increase over the corresponding prior year quarter) and $92.0 million excluding reimbursable expenses (representing a $7.6 million or 9.0% increase over the corresp

November 1, 2011 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 1, 2011 (November 1, 2011

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 1, 2011 (November 1, 2011) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incor

October 31, 2011 8-K/A

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 31, 2011 (October 31, 2011) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other j

October 31, 2011 EX-99.1

Duff & Phelps Expands European Presence With Acquisition of MCR

EXHIBIT 99.1 Duff & Phelps Expands European Presence With Acquisition of MCR Addition of UK-Based Restructuring and Turnaround Firm Expands Duff & Phelps' European Presence and Strengthens Global Restructuring Advisory Practice NEW YORK–October 31, 2011–Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking services firm, today announced that it has

October 31, 2011 8-K

Unregistered Sales of Equity Securities, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 31, 2011 (October 31, 2011) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incor

October 17, 2011 EX-10.1

FOURTH AMENDMENT TO CREDIT AGREEMENT

EXHIBIT 10.1 FOURTH AMENDMENT TO CREDIT AGREEMENT This FOURTH AMENDMENT to Credit Agreement (this “Amendment”) is entered into as of October 13, 2011, among DUFF & PHELPS, LLC, a Delaware limited liability company (the “Borrower”), DUFF & PHELPS ACQUISITIONS, LLC (“Holdings”), CHANIN CAPITAL PARTNERS LLC (“Chanin”), and RASH & ASSOCIATES, L.P. (“Rash” and together with Holdings and Chanin, each a

October 17, 2011 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 17, 2011 (October 13, 2011) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incor

September 15, 2011 EX-24

POWER OF ATTORNEY

POWER OF ATTORNEY KNOW ALL BY THESE PRESENTS, that the undersigned hereby constitutes and appoints each of Edward Forman, Patrick Puzzuoli and Noah Gottdiener as his true and lawful attorney-in-fact, solely for the following purposes, and hereby confers upon each such attorney-in-fact full power and authority to perform each and all of the following acts in the name of and on behalf of the undersigned.

September 15, 2011 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) September 15, 2011 (September 13,

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) September 15, 2011 (September 13, 2011) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of i

September 15, 2011 EX-99.1

Duff & Phelps Appoints John Kritzmacher to Board of Directors

Duff & Phelps Appoints John Kritzmacher to Board of Directors New York, NY, September 13, 2011 - Duff & Phelps Corporation (NYSE: DUF), a leading independent provider of financial advisory and investment banking services, announced today that John Kritzmacher has joined the company's board of directors.

August 18, 2011 LETTER

LETTER

August 18, 2011 Via E-mail Patrick Puzzuoli Chief Financial Officer Duff & Phelps Corporation 55 East 52 nd Street, 31 st Floor New York, New York 10055 Re: Duff & Phelps Corporation Form 10-K Filed February 24, 2011 File No.

August 15, 2011 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 15, 2011 (August 15, 2011)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 15, 2011 (August 15, 2011) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorpo

August 15, 2011 EX-10.1

THIRD AMENDMENT TO CREDIT AGREEMENT

THIRD AMENDMENT TO CREDIT AGREEMENT This THIRD AMENDMENT to Credit Agreement (this “Amendment”) is entered into as of August 15, 2011, among DUFF & PHELPS, LLC, a Delaware limited liability company (the “Borrower”), DUFF & PHELPS ACQUISITIONS, LLC (“Holdings”), CHANIN CAPITAL PARTNERS LLC (“Chanin”), and RASH & ASSOCIATES, L.

August 12, 2011 CORRESP

Duff & Phelps Corporation 55 East 52nd Street, 31st Floor New York, New York 10055 (212) 871-2000

Duff & Phelps Corporation 55 East 52nd Street, 31st Floor New York, New York 10055 (212) 871-2000 August 12, 2011 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance Washington, D.

August 9, 2011 LETTER

LETTER

July 28, 2011 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended June 30, 2011 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact na

July 27, 2011 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) July 27, 2011 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commission

July 27, 2011 EX-99.1

DUFF & PHELPS REPORTS 2011 SECOND QUARTER RESULTS AND DECLARES QUARTERLY DIVIDEND

DUFF & PHELPS REPORTS 2011 SECOND QUARTER RESULTS AND DECLARES QUARTERLY DIVIDEND HIGHLIGHTS: - Quarterly revenues of $91.

July 5, 2011 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) July 5, 2011 (June 30, 2011) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporatio

July 5, 2011 EX-99.1

July 05, 2011 09:00 AM Eastern Daylight Time

July 05, 2011 09:00 AM Eastern Daylight Time Duff & Phelps Acquires Growth Capital Partners Addition of Texas-Based, Middle Market Investment Banking Firm Enhances Duff & Phelps' Energy Industry Expertise NEW YORK-(BUSINESS WIRE)-Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking services firm, today announced that it has acquired Growth Capital Partners.

May 16, 2011 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 16, 2011 (May 12, 2011) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation

May 12, 2011 424B7

Duff & Phelps Corporation Class A Common Stock

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No.

April 28, 2011 10-Q

UNITED STATES

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended March 31, 2011 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact name of registrant

April 28, 2011 EX-10.1

FORM OF PERFORMANCE-VESTING RESTRICTED STOCK AWARD AGREEMENT UNDER THE DUFF & PHELPS CORPORATION AMENDED AND RESTATED 2007 OMNIBUS STOCK INCENTIVE PLAN

EXHIBIT 10.1 FORM OF PERFORMANCE-VESTING RESTRICTED STOCK AWARD AGREEMENT UNDER THE DUFF & PHELPS CORPORATION AMENDED AND RESTATED 2007 OMNIBUS STOCK INCENTIVE PLAN This Performance-Vesting Restricted Stock Award Agreement (this ?Agreement?), dated as of (the ?Date of Grant?), is made by and between Duff & Phelps Corporation, a Delaware corporation (the ?Company?) and (the ?Participant?). Capitali

April 27, 2011 EX-99.1

DUFF & PHELPS REPORTS 2011 FIRST QUARTER RESULTS AND DECLARES QUARTERLY DIVIDEND

FOR IMMEDIATE RELEASE DUFF & PHELPS REPORTS 2011 FIRST QUARTER RESULTS AND DECLARES QUARTERLY DIVIDEND HIGHLIGHTS: - Quarterly revenue of $86.

April 27, 2011 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) April 27, 2011 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commission

March 28, 2011 DEF 14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Duff & Phelps Corporation NOTICE OF ANNUAL MEETING OF STOCKHOLDERS May 12, 2011 DUFF & PHELPS CORPORATION TABLE OF CONTENTS PROXY STATEMENT FOR

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant x Filed by a Party other than the Registrant o Check the appropriate box: o Preliminary Proxy Statement o Confidential, for Use of the Commission only (as permitted by Rule 14a-6(e)(2)) x Definitive Proxy Statement o Definitive Additional Materials o Soliciting Material Pursuant to §240.

March 28, 2011 DEFA14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Duff & Phelps Corporation

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant x Filed by a Party other than the Registrant o Check the appropriate box: o Preliminary Proxy Statement o Confidential, for Use of the Commission only (as permitted by Rule 14a-6(e)(2)) o Definitive Proxy Statement x Definitive Additional Materials o Soliciting Material Pursuant to §240.

March 16, 2011 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) March 16, 2011 (March 11, 2011) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorpora

March 8, 2011 EX-24

POWER OF ATTORNEY

POWER OF ATTORNEY KNOW ALL BY THESE PRESENTS, that the undersigned hereby constitutes and appoints each of Edward Forman, Jacob Silverman and Noah Gottdiener as his true and lawful attorney-in-fact, solely for the following purposes, and hereby confers upon each such attorney-in-fact full power and authority to perform each and all of the following acts in the name of and on behalf of the undersigned.

March 7, 2011 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) March 7, 2011 (March 7, 2011) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporati

March 7, 2011 EX-10.1

EXHIBIT A

Mr. Patrick Puzzuoli Duff & Phelps Corporation 55 E 52nd St., Fl. 31 New York, NY 10055 March 7, 2011 Dear Patrick: Effective March 7, 2011, you have been appointed Executive Vice President and Chief Financial Officer (?CFO?) of Duff & Phelps Corporation (the ?Company?). In connection with your serving the Company as CFO, this letter agreement sets forth the terms and conditions under which you ma

March 7, 2011 EX-99.1

Duff & Phelps Names New Head of Investment

FOR IMMEDIATE RELEASE Duff & Phelps Names New Head of Investment Banking and New Chief Financial Officer NEW YORK, March 7, 2011 — Duff & Phelps Corporation (NYSE: DUF), a leading independent provider of financial advisory and investment banking services, today announced that Jacob Silverman has been named leader of the Investment Banking segment.

March 2, 2011 SC 13G/A

SC 13G/A

OMB APPROVAL OMB Number: 3235-0145 Estimated average burden hours per response 11 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

March 2, 2011 424B7

Duff & Phelps Corporation Class A Common Stock

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No.

February 28, 2011 EX-10.1

SECOND AMENDMENT TO CREDIT AGREEMENT

SECOND AMENDMENT TO CREDIT AGREEMENT This SECOND AMENDMENT TO CREDIT AGREEMENT (this “Amendment”) is entered into as of February 23, 2011, among DUFF & PHELPS, LLC, a Delaware limited liability company (the “Borrower”), DUFF & PHELPS ACQUISITIONS, LLC (“Holdings”), CHANIN CAPITAL PARTNERS LLC (“Chanin”), and RASH & ASSOCIATES, L.

February 28, 2011 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 28, 2011 (February 23, 2011) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of inc

February 24, 2011 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the year ended December 31, 2010 or ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to . Commission File No. 001-33693 DUFF & PHELPS CORPORATION (Exact n

February 24, 2011 EX-21.1

DUFF & PHELPS CORPORATION AND SUBSIDIARIES LIST OF SUBSIDIARIES AS OF DECEMBER 31, 2010

EXHIBIT 21.1 DUFF & PHELPS CORPORATION AND SUBSIDIARIES LIST OF SUBSIDIARIES AS OF DECEMBER 31, 2010 Corporate Name Jurisdiction of Incorporation Chanin & Company, LLC California Chanin Advisors, LLC Delaware Chanin Capital Partners, LLC California D&P Canada Acquisition Corp Canada D&P International Holdings, LLC Delaware Duff & Phelps (H.K.) Holdings Limited Hong Kong SAR Duff & Phelps Acquisiti

February 23, 2011 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 23, 2011 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of (Commission (IRS Employ

February 23, 2011 EX-99.1

DUFF & PHELPS REPORTS 2010 FOURTH QUARTER AND FULL YEAR RESULTS AND DECLARES QUARTERLY DIVIDEND

FOR IMMEDIATE RELEASE DUFF & PHELPS REPORTS 2010 FOURTH QUARTER AND FULL YEAR RESULTS AND DECLARES QUARTERLY DIVIDEND FOURTH QUARTER AND RECENT HIGHLIGHTS: - Quarterly revenues of $105.

February 14, 2011 SC 13G/A

SC 13G/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* Duff & Phelps Corp (Name of Issuer) Class A Common Stock (Title of Class of Securities) 26433B107 (CUSIP Number) December 31, 2010 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which t

February 9, 2011 SC 13G/A

SC 13G/A

OMB APPROVAL OMB Number: 3235-0145 Estimated average burden hours per response 11 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

February 9, 2011 SC 13G/A

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)1 Duff & Phelps Corp New (Name of Issuer) Common Stock, $0.01 par value (Title of Class of Securities) (CUSIP Number) De

Amendment No. 1 to Schedule 13G SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)1 Duff & Phelps Corp New (Name of Issuer) Common Stock, $0.01 par value (Title of Class of Securities) 26433B107 (CUSIP Number) December 31, 2010 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designa

January 31, 2011 SC 13G/A

SC 13G/A

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) Information statement pursuant to Rules 13d-1 and 13d-2 Under the Securities Exchange Act of 1934 (Amendment No.1) Duff & Phelps Corporation (Name of Issuer) Class A Common Stock (Title of Class of Securities) 26433B107 (CUSIP Number) Date of Event Which Requires Filing of this Statement: December 31, 2010 *The r

January 27, 2011 SC 13G

SC 13G

January 18, 2011 Securities and Exchange Commission 450 Fifth Street NW Washington, DC 20549 RE: Schedule 13G Duff & Phelps Corp.

December 17, 2010 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) December 17, 2010 (December 15, 2010) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of inc

December 17, 2010 EX-99.1

FOR IMMEDIATE RELEASE

FOR IMMEDIATE RELEASE Duff & Phelps Acquires Dynamic Credit Partners? U.S. Consulting Business and June Consulting Group Addition of 22 Professionals Expands Complex Valuation Capabilities and Legal Management Services NEW YORK, New York, Date - Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking firm, today announced that it has acquired Dynamic

November 12, 2010 424B7

Duff & Phelps Corporation Class A Common Stock

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No.

November 9, 2010 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 9, 2010 (November 8, 2010) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incor

November 9, 2010 EX-10.1

FIRST AMENDMENT TO CREDIT AGREEMENT

FIRST AMENDMENT TO CREDIT AGREEMENT This FIRST AMENDMENT to Credit Agreement (this “Amendment”) is entered into as of November 8, 2010, among DUFF & PHELPS, LLC, a Delaware limited liability company (the “Borrower”), DUFF & PHELPS ACQUISITIONS, LLC (“Holdings”), CHANIN CAPITAL PARTNERS LLC (“Chanin”), and RASH & ASSOCIATES, L.

October 29, 2010 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended September 30, 2010 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact name of registr

October 29, 2010 EX-99.2

CORRECTING and REPLACING Duff & Phelps Reports Third Quarter 2010 Results and Declares Quarterly Dividend CORRECTION...by Duff & Phelps Corporation NEW YORK--October 28, 2010--In the "Results Of Operations By Segment" financial table, the entries for

FOR IMMEDIATE RELEASE CORRECTING and REPLACING Duff & Phelps Reports Third Quarter 2010 Results and Declares Quarterly Dividend CORRECTION.

October 29, 2010 8-K/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A Amendment No. 1 CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A Amendment No. 1 CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 29, 2010 (October 28, 2010) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jur

October 28, 2010 EX-99.1

DUFF & PHELPS REPORTS THIRD QUARTER 2010 RESULTS AND DECLARES QUARTERLY DIVIDEND

FOR IMMEDIATE RELEASE DUFF & PHELPS REPORTS THIRD QUARTER 2010 RESULTS AND DECLARES QUARTERLY DIVIDEND HIGHLIGHTS: - Quarterly revenues of $86.

October 28, 2010 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 28, 2010 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commissi

September 15, 2010 S-8

As filed with the Securities and Exchange Commission on September 15, 2010

As filed with the Securities and Exchange Commission on September 15, 2010 Registration No.

August 12, 2010 424B7

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No. 333-162551 Duff & Phelps Corporation Class A Common Stock

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No.

July 30, 2010 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended June 30, 2010 OR ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact name of registrant a

July 29, 2010 EX-99.1

DUFF & PHELPS REPORTS SECOND QUARTER 2010 RESULTS AND DECLARES QUARTERLY DIVIDEND

FOR IMMEDIATE RELEASE DUFF & PHELPS REPORTS SECOND QUARTER 2010 RESULTS AND DECLARES QUARTERLY DIVIDEND HIGHLIGHTS: - Quarterly revenues of $90.

July 29, 2010 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) July 29, 2010 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commission

June 17, 2010 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) June 17, 2010 (June 15, 2010) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporati

June 17, 2010 EX-99.1

Duff & Phelps Acquires Cole & Partners

FOR IMMEDIATE RELEASE Duff & Phelps Acquires Cole & Partners Addition of Leading Canadian Financial Advisory Firm Establishes Duff & Phelps’ Presence in Canada NEW YORK, June 15, 2010 - Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking firm, today announced that it has acquired Cole & Partners, a Toronto-based independent financial advisory practice comprised of approximately 20 client service professionals.

May 13, 2010 424B7

Duff & Phelps Corporation Class A Common Stock

Prospectus Supplement Filed Pursuant to Rule 424(b)(7) (To Prospectus dated October 26, 2009) Registration No.

May 10, 2010 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 7, 2010 (May 6, 2010)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 7, 2010 (May 6, 2010) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation)

April 30, 2010 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended March 31, 2010 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact name of registrant

April 29, 2010 EX-99.1

DUFF & PHELPS REPORTS FIRST QUARTER 2010 FINANCIAL RESULTS

DUFF & PHELPS DUFF & PHELPS REPORTS FIRST QUARTER 2010 FINANCIAL RESULTS HIGHLIGHTS: · Revenues of $92.

April 29, 2010 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) April 29, 2010 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commission

April 26, 2010 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) April 26, 2010 (April 22, 2010) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorpora

April 23, 2010 DEFA14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Duff & Phelps Corporation Supplement to Notice of Annual Meeting and Proxy Statement

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant x Filed by a Party other than the Registrant o Check the appropriate box: o Preliminary Proxy Statement o Confidential, for Use of the Commission only (as permitted by Rule 14a-6(e)(2)) o Definitive Proxy Statement x Definitive Additional Materials o Soliciting Material Pursuant to §240.

March 22, 2010 DEFA14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant x Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission ? Definitive Proxy Statement only (as permitted by Rule 14a-6(e)(2)) x Definitive Additional Materials ? Soliciting Material Pursuant to ?240.

March 22, 2010 DEF 14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Duff & Phelps Corporation NOTICE OF ANNUAL MEETING OF STOCKHOLDERS May 6, 2010 DUFF & PHELPS CORPORATION TABLE OF CONTENTS PROXY STATEMENT FOR A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant x Filed by a Party other than the Registrant o Check the appropriate box: o Preliminary Proxy Statement o Confidential, for Use of the Commission only (as permitted by Rule 14a-6(e)(2)) x Definitive Proxy Statement o Definitive Additional Materials o Soliciting Material Pursuant to §240.

March 3, 2010 424B7

Prospectus Supplement (To Prospectus dated October 26, 2009) Filed Pursuant to Rule 424(b)(7) Registration No. 333-162551

Prospectus Supplement (To Prospectus dated October 26, 2009) Filed Pursuant to Rule 424(b)(7) Registration No.

February 25, 2010 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the year ended December 31, 2009 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to . Commission File No. 001-33693 DUFF & PHELPS CORPORATION (Exact n

February 25, 2010 EX-21.1

DUFF & PHELPS CORPORATION AND SUBSIDIARIES LIST OF SUBSIDIARIES AS OF DECEMBER 31, 2009

EXHIBIT 21.1 DUFF & PHELPS CORPORATION AND SUBSIDIARIES LIST OF SUBSIDIARIES AS OF DECEMBER 31, 2009 Corporate Name Jurisdiction of Incorporation Chanin & Company, LLC California Chanin Advisors, LLC Delaware Chanin Capital Partners, LLC California D&P International Holdings, LLC Delaware Duff & Phelps (H.K.) Holdings Limited Hong Kong SAR Duff & Phelps Acquisitions, LLC Delaware Duff & Phelps B.V

February 23, 2010 EX-99.1

DUFF & PHELPS REPORTS 2009 FULL YEAR AND FOURTH QUARTER FINANCIAL RESULTS AND DECLARES QUARTERLY DIVIDEND

DUFF & PHELPS DUFF & PHELPS REPORTS 2009 FULL YEAR AND FOURTH QUARTER FINANCIAL RESULTS AND DECLARES QUARTERLY DIVIDEND FULL YEAR HIGHLIGHTS: · Full year revenues of $382.

February 23, 2010 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 23, 2010 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commiss

February 16, 2010 SC 13G/A

SC 13G/A

SCHEDULE 13G/A FILINGS DATE:December 31, 2009 SECURITY:DUFF & PHELPS CORPORATION CUSIP:26433B107 CIK#:0001397821 IRS#:208893559 Exchange:NYSE ADDRESS:55 EAST 52ND STREET NEW YORK, NY 10055 SOLE VOTING SHARES: -0- SHARED DISPOSITIVE SHARES : -0- AGGREGATE AMOUNT: -0- SHARES OUTSTANDING: -0- % OWNED BY LOOMIS: 0% LOOMIS CIK#:0000312348 LOOMIS IRS#:043200030 LOOMIS PASSWORD:xxxxxxxx SECURITIES AND EXCHANGE COMMISSION Washington, D.

February 12, 2010 SC 13G/A

SCHEDULE 13G

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* Duff & Phelps Corporation (Name of Issuer) Class A Common Stock (Title of Class of Securities) 26433B107 (CUSIP Number) December 31, 2009 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to

February 11, 2010 SC 13G

SC 13G

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* Duff & Phelps Corp (Name of Issuer) Class A Common Stock (Title of Class of Securities) 26433B107 (CUSIP Number) December 31, 2009 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which th

February 11, 2010 SC 13G

SC 13G

OMB APPROVAL OMB Number: 3235-0145 Expires: February 28, 2009 Estimated average burden hours per response 11 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

February 11, 2010 SC 13G/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b)(c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendmen

Schedule 13G Amendment No. 2 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b)(c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendment No. 2)* DUFF & PHELPS CORPORATION (Name of issuer) CLASS A COMMON STOCK (Title of class of securities) 26433B107 (CUSIP

February 9, 2010 SC 13G

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )1 Duff & Phelps Corp (Name of Issuer) Common Stock, $0.01 par value (Title of Class of Securities) (CUSIP Number) Decembe

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )1 Duff & Phelps Corp (Name of Issuer) Common Stock, $0.01 par value (Title of Class of Securities) 26433B107 (CUSIP Number) December 31, 2009 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Sc

February 2, 2010 SC 13G

SC 13G

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) Information statement pursuant to Rules 13d-1 and 13d-2 Under the Securities Exchange Act of 1934 (Amendment No.) Duff & Phelps Corporation (Name of Issuer) Class A Common Stock (Title of Class of Securities) 26433B107 (CUSIP Number) Date of Event Which Requires Filing of this Statement: December 31, 2009 *The re

November 16, 2009 424B7

Duff & Phelps Corporation Class A Common Stock

Filed Pursuant to Rule 424(b)(7) Registration No. 333-162551 Prospectus Supplement (To Prospectus dated October 26, 2009) Duff & Phelps Corporation Class A Common Stock This prospectus supplement supplements and amends the prospectus dated October 26, 2009 relating, in part, to the resale from time to time of up to 19,618,979 shares of our Class A common stock by the selling stockholders described

November 9, 2009 EX-1.1

Duff & Phelps Corporation Class A Common Stock, par value $.01 Underwriting Agreement

EXHIBIT 1.1 Duff & Phelps Corporation Class A Common Stock, par value $.01 Underwriting Agreement November 4, 2009 Goldman, Sachs & Co. 85 Broad Street New York, New York 10004 As representative of the several Underwriters named in Schedule I hereto Ladies and Gentlemen: Duff & Phelps Corporation, a Delaware corporation (the “Company”), proposes, subject to the terms and conditions stated herein,

November 9, 2009 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 9, 2009 (November 4, 2009) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incor

November 6, 2009 424B5

2,500,000 Shares Duff & Phelps Corporation Class A Common Stock Goldman, Sachs & Co. ABOUT THIS PROSPECTUS SUPPLEMENT CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS PROSPECTUS SUPPLEMENT SUMMARY THE OFFERING USE OF PROCEEDS PRICE RANGE OF CLAS

Filed Pursuant to Rule 424(b)(5) Registration No. 333-162551 Prospectus Supplement (To Prospectus dated October 26, 2009) 2,500,000 Shares Duff & Phelps Corporation Class A Common Stock We sold 2,500,000 shares of our Class A common stock to the underwriter at a price of $15.00 per share for an aggregate of $37,500,000, and the underwriter is offering such shares to the public at a price of $15.50

November 4, 2009 FWP

Filed Pursuant to Rule 433

Filed Pursuant to Rule 433 Registration No. 333-162551 DUFF & PHELPS ANNOUNCES COMMON STOCK OFFERING OF 2.5 MILLION SHARES New York, NY, November 4, 2009 – Duff & Phelps Corporation (NYSE: DUF), a leading independent financial advisory and investment banking firm, today announced that it has agreed to sell 2,500,000 shares in an underwritten public offering of Class A common stock. Duff & Phelps i

November 4, 2009 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended September 30, 2009 OR ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact name of registr

November 3, 2009 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 3, 2009 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commissi

November 3, 2009 EX-99.1

DUFF & PHELPS REPORTS THIRD QUARTER 2009 FINANCIAL RESULTS AND DECLARES QUARTERLY DIVIDEND

DUFF & PHELPS REPORTS THIRD QUARTER 2009 FINANCIAL RESULTS AND DECLARES QUARTERLY DIVIDEND RECENT HIGHLIGHTS · Third quarter revenues excluding reimbursable expenses of $93.

October 16, 2009 EX-12.1

Computation of Ratio of Earnings to Fixed Charges(1)

Exhibit 12.1 Computation of Ratio of Earnings to Fixed Charges(1) Initial Successor Predecessor Predecessor(2) Six Months Period from Period from Period from Period from Ended Year Ended October 4 to January 1 to Year Ended Year Ended March 15 to January 1 to June 30, December 31, December 31, October 3, December 31, December 31, December 31, March 14, 2009 2008 2007 2007 2006 2005 2004 2004 Incom

October 16, 2009 S-3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Duff & Phelps Corporation CALCULATION OF REGISTRATION FEE EXPLANATORY NOTE SUBJECT TO COMPLETION, DATED OCTOBER 16, 2009 $381,262,500 Class A Common Stock Preferred Stock Debt Se

As filed with the Securities and Exchange Commission on October 16, 2009 Registration No.

October 16, 2009 EX-99.2

Consolidated Statements of Operations (In thousands, except per share data)

Exhibit 99.2 Item 6. Selected Financial Data The following table sets forth the historical selected financial data for the Company for all periods presented. For more information on our historical financial information and Adjusted EBITDA, see Item 7. “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and Item 8. “Financial Statements and Supplemental Data.” Co

October 16, 2009 8-K

Other Events, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 16, 2009 DUFF & PHELPS CORPORATION (Exact name of Registrant as specified in its charter) Commission File No. 001-33693 Delaware 20-8893559 (State or Other Jurisdiction of Inc

October 16, 2009 EX-99.3

Summary of Equity Based Compensation Expense (In thousands)

Exhibit 99.3 Item 7. Management?s Discussion and Analysis of Financial Condition and Results of Operations. Overview The following results of operations, analysis and discussion present an aggregation of certain periods to help provide a full-year presentation of our results for comparability purposes. These aggregated results are a non-GAAP financial measure. For example, the Predecessor period f

October 16, 2009 EX-99.1

Part I

EXHIBIT 99.1 In this report, references to the ?Company,? ?we,? ?us,? ?our? and ?Successor? refer to Duff & Phelps Corporation and its consolidated subsidiaries during the period subsequent to October 3, 2007, the date we consummated our initial public offering (?IPO?) and related transactions. Prior to the IPO, Duff & Phelps Acquisitions, LLC and its subsidiaries (?D&P Acquisitions? or ?Predecess

October 16, 2009 EX-99.4

INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

Exhibit 99.4 Item 8. Financial Statements and Supplemental Data. The Company’s consolidated financial statements listed in the “Index to Consolidated Financial Statements” described at F-1 are incorporated by reference herein. 1 INDEX TO CONSOLIDATED FINANCIAL STATEMENTS Audited Consolidated Financial Statements: Report of Independent Registered Public Accounting Firm F-2 Consolidated Statements o

October 6, 2009 EX-10.1

FIRST AMENDMENT TO THE EXCHANGE AGREEMENT BY AND AMONG DUFF & PHELPS ACQUISITIONS, LLC LM DUFF HOLDINGS, LLC LOVELL MINNICK EQUITY PARTNERS LP VESTAR CAPITAL PARTNERS IV, L.P. VESTAR/D&P HOLDINGS LLC the individual MEMBERS listed on the signature pag

FIRST AMENDMENT TO THE EXCHANGE AGREEMENT BY AND AMONG DUFF & PHELPS ACQUISITIONS, LLC LM DUFF HOLDINGS, LLC LOVELL MINNICK EQUITY PARTNERS LP VESTAR CAPITAL PARTNERS IV, L.

October 6, 2009 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 6, 2009 (October 5, 2009) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorpo

August 4, 2009 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended June 30, 2009 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact name of registrant a

August 3, 2009 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 3, 2009 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commission

August 3, 2009 EX-99.1

DUFF & PHELPS REPORTS SECOND QUARTER 2009 FINANCIAL RESULTS AND DECLARES QUARTERLY DIVIDEND

DUFF & PHELPS REPORTS SECOND QUARTER 2009 FINANCIAL RESULTS AND DECLARES QUARTERLY DIVIDEND RECENT HIGHLIGHTS · Second quarter revenues excluding reimbursable expenses of $90.

July 20, 2009 LETTER

LETTER

Mail Stop 4561 June 10, 2009 (via U. S. Mail and facsimile ((917) 702-8658) Mr. Noah Gottdiener Chairman and Chief Executive Officer Duff & Phelps Corporation 55 East 52nd Street, 31st Floor New York, New York 10055 Re: Duff & Phelps Corporation File No. 001-33693 Form 10-K for the fiscal year ended December 31, 2008 Dear Mr. Gottdiener: We have reviewed your filings and have the following comment

July 17, 2009 EX-99.1

CREDIT AGREEMENT Dated as of July 15, 2009 DUFF & PHELPS, LLC, as the Borrower, BANK OF AMERICA, N.A., as Administrative Agent and L/C Issuer, The Other Lenders Party Hereto Table of Contents

Published CUSIP Number: CREDIT AGREEMENT Dated as of July 15, 2009 among DUFF & PHELPS, LLC, as the Borrower, BANK OF AMERICA, N.

July 17, 2009 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) July 17, 2009 (July 15, 2009) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporati

July 15, 2009 LETTER

LETTER

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 DIVISION OF CORPORATION FINANCE Mail Stop 4561 July 15, 2009 Via US Mail and Facsimile to (212) 450-2801 Mr. Noah Gottdiener Chairman and Chief Executive Officer Duff & Phelps Corporation 55 East 52 nd Street, 31 st Floor New York, New York 10055 Re: Duff & Phelps Corporation Form 10-K for Fiscal Year Ended December 31, 2008 F

June 16, 2009 CORRESP

Duff & Phelps Corporation 55 East 52nd Street, 31st Floor New York, New York 10055 (212) 871-2000

Duff & Phelps Corporation 55 East 52nd Street, 31st Floor New York, New York 10055 (212) 871-2000 June 16, 2009 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

May 29, 2009 SC 13D/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 1)* Duff & Phelps Corporation (Name of Issuer) Class A Common Stock, par value $0.01 per share (Title of Cla

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 1)* Duff & Phelps Corporation (Name of Issuer) Class A Common Stock, par value $0.01 per share (Title of Class of Securities) 26433B107 (CUSIP Number) Sander Levy Vestar Capital Partners IV, L.P. 245 Park Avenue, 41st Floor New York, New Yo

May 29, 2009 SC 13D/A

UNITED STATES

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D/A Under the Securities Exchange Act of 1934 (Amendment No. 1) Duff & Phelps Corporation (Name of Issuer) Class A Common Stock, par value $0.01 per share (Title of Class of Securities) 26433B107 (CUSIP Number) Jennings J. Newcom Lovell Minnick Partners LLC 2141 Rosecrans Avenue Suite 5150 El Segundo, CA 90245 (Name

May 26, 2009 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 26, 2009 (May 22, 2009) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation

May 18, 2009 EX-1.1

Duff & Phelps Corporation Class A Common Stock, par value $.01 Underwriting Agreement

Exhibit 1.1 Duff & Phelps Corporation Class A Common Stock, par value $.01 Underwriting Agreement May 13, 2009 Goldman, Sachs & Co. 85 Broad Street New York, New York 10004 As representative of the several Underwriters named in Schedule I hereto Ladies and Gentlemen: Duff & Phelps Corporation, a Delaware corporation (the “Company”), proposes, subject to the terms and conditions stated herein, to i

May 18, 2009 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 18, 2009 (May 13, 2009) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation

May 14, 2009 424B5

7,000,000 Shares Duff & Phelps Corporation Class A Common Stock Goldman, Sachs & Co. ABOUT THIS PROSPECTUS SUPPLEMENT CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS PROSPECTUS SUPPLEMENT SUMMARY THE OFFERING USE OF PROCEEDS PRICE RANGE OF CLAS

Filed Pursuant to Rule 424(b)(5) Registration No. 333-158739 Prospectus Supplement (To Prospectus dated May 4, 2009) 7,000,000 Shares Duff & Phelps Corporation Class A Common Stock We are offering 7,000,000 shares of Class A common stock of Duff & Phelps Corporation. Our Class A common stock is listed on the New York Stock Exchange under the symbol “DUF.” The last reported sale price of our Class

May 13, 2009 FWP

DUFF & PHELPS CORPORATION Final Term Sheet

Issuer Free Writing Prospectus Filed Pursuant to Rule 433 May 13, 2009 Registration Statement No.

May 5, 2009 EX-99.1

DUFF & PHELPS REPORTS FIRST QUARTER 2009 FINANCIAL RESULTS FIRST QUARTER HIGHLIGHTS:

DUFF & PHELPS DUFF & PHELPS REPORTS FIRST QUARTER 2009 FINANCIAL RESULTS FIRST QUARTER HIGHLIGHTS: ? Revenues excluding reimbursable expenses of $89.

May 5, 2009 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended March 31, 2009 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number: 001-33693 DUFF & PHELPS CORPORATION (Exact name of registrant

May 5, 2009 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 5, 2009 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commission Fi

May 5, 2009 424B5

Subject to Completion, dated May 5, 2009. 8,900,000 Shares Duff & Phelps Corporation Class A Common Stock Goldman, Sachs & Co. ABOUT THIS PROSPECTUS SUPPLEMENT CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS PROSPECTUS SUPPLEMENT SUMMARY THE OF

The information in this preliminary prospectus supplement is not complete and may be changed.

April 24, 2009 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) April 24, 2009 (April 23, 2009) Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorpora

April 24, 2009 EX-25.1

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTE

EXHIBIT 25.1 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTEE PURSUANT TO SECTION 305(b)(2) [ ] THE BANK OF NEW YORK MELLON (Exact name of trustee as specified in its charter) New York (Jurisdictio

April 24, 2009 S-3

As filed with the Securities and Exchange Commission on April 23, 2009

As filed with the Securities and Exchange Commission on April 23, 2009 Registration No.

April 24, 2009 EX-12.1

Duff & Phelps Corporation Computation of Ratios of Earnings to Fixed Charges

EXHIBIT 12.1 Duff & Phelps Corporation Computation of Ratios of Earnings to Fixed Charges Successor Predecessor Initial Predecessor(2) Year Ended December 31, 2008 Period from October 4 to December 31, 2007 Period from January 1 to October 3, 2007 Year Ended December 31, 2006 Year Ended December 31, 2005 Period from March 15, 2004 - December 31, 2004 Period from January 1, 2004 - March 14, 2004 In

April 24, 2009 EX-4.1

=================================================================== DUFF & PHELPS CORPORATION Dated as of DEBT SECURITIES THE BANK OF NEW YORK MELLON TABLE OF CONTENTS*

EXHIBIT 4.1 =================================================================== DUFF & PHELPS CORPORATION - INDENTURE Dated as of [Date] - DEBT SECURITIES THE BANK OF NEW YORK MELLON Trustee =================================================================== TABLE OF CONTENTS* ARTICLE I PAGE DEFINITIONS Section 1.01 Definitions. 1 ARTICLE II FORMS OF SECURITIES Section 2.01 Terms of the Securities

March 16, 2009 DEF 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ý Filed by a Party other than the Registran

Use these links to rapidly review the document TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

March 16, 2009 DEFA14A

UNITED STATES

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant x Filed by a Party other than the Registrant o Check the appropriate box: o Preliminary Proxy Statement o Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) o Defin

February 26, 2009 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 26, 2009 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commiss

February 26, 2009 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the year ended December 31, 2008 or o TRANSITION REPORT PURSUANT TO SECTION 1

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the year ended December 31, 2008 or o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to . Commission File No. 001-33693 DUFF & PHELPS CO

February 26, 2009 EX-21.1

DUFF & PHELPS CORPORATION AND SUBSIDIARIES LIST OF SUBSIDIARIES AS OF DECEMBER 31, 2008 Corporate Name Jurisdiction of Incorporation Chanin & Company, LLC California Chanin Advisors, LLC Delaware Chanin Capital Partners, LLC California D&P Netherland

EXHIBIT 21.1 DUFF & PHELPS CORPORATION AND SUBSIDIARIES LIST OF SUBSIDIARIES AS OF DECEMBER 31, 2008 Corporate Name Jurisdiction of Incorporation Chanin & Company, LLC California Chanin Advisors, LLC Delaware Chanin Capital Partners, LLC California D&P Netherlands Holdings, LLC Delaware Duff & Phelps (H.K.) Holdings Limited Hong Kong SAR Duff & Phelps Acquisitions, LLC Delaware Duff & Phelps B.V.

February 26, 2009 EX-99.1

DUFF & PHELPS REPORTS 2008 FULL-YEAR AND FOURTH QUARTER FINANCIAL RESULTS

Exhibit 99.1 DUFF & PHELPS DUFF & PHELPS REPORTS 2008 FULL-YEAR AND FOURTH QUARTER FINANCIAL RESULTS FULL-YEAR HIGHLIGHTS: ? Full-year revenues excluding reimbursable expenses of $381.5 million, representing 11.8% growth compared to the prior year ? Adjusted EBITDA(1) of $73.6 million, representing 19.3% margin ? Adjusted pro forma net income per share(1) of $1.05, representing 12.9% growth from t

February 17, 2009 SC 13G

SCHEDULE 13G

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* Duff & Phelps Corporation (Name of Issuer) Class A Common Stock (Title of Class of Securities) 26433B107 (CUSIP Number) December 31, 2008 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to w

February 13, 2009 SC 13G/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b)(c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendmen

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b)(c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendment No. 1)* DUFF & PHELPS CORPORATION (Name of Issuer) CLASS A COMMON STOCK (Title of Class of Securities) 26433B107 (CUSIP Number) December 31, 2008 (D

February 13, 2009 SC 13G

SC 13G

SCHEDULE 13G FILINGS DATE:December 31, 2008 SECURITY:DUFF & PHELPS CORPORATION CUSIP:26433B107 CIK#:0001397821 IRS#:208893559 Exchange:NYSE ADDRESS:55 EAST 52ND STREET NEW YORK, NY 10055 SOLE VOTING SHARES: 652,946 SHARED DISPOSITIVE SHARES : -0- AGGREGATE AMOUNT: 882,366 SHARES OUTSTANDING: 14,592,000 % OWNED BY LOOMIS: 6.

January 29, 2009 SC 13G/A

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No. 1) DUFF & PHELPS CORPORATION (Name of Issuer) Class A Common Stock, $0.01 par value (Title of Class of Securities) (CUSIP

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No. 1) DUFF & PHELPS CORPORATION - (Name of Issuer) Class A Common Stock, $0.01 par value - (Title of Class of Securities) 26433B107 - (CUSIP Number) December 31, 2008 - (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pu

November 6, 2008 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the quarterly period ended September 30, 2008 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File Number 001-33693 DUFF & PHELPS CORPORATION (Exact name of registra

November 6, 2008 8-K

Results of Operations and Financial Condition, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 6, 2008 Duff & Phelps Corporation (Exact name of registrant as specified in its charter) Delaware 001-33693 20-8893559 (State or other jurisdiction of incorporation) (Commissi

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