Mendon Capital Advisors Corp ownership in OSB / Old Second Bancorp, Inc.

Old Second Bancorp, Inc.

DE ˙ DB ˙ US6802771005

18,20 € ↑0,60 (3,41%)

2026-06-05
DEL PRIS

Security	DE:OSB / Old Second Bancorp, Inc.
Institution	Mendon Capital Advisors Corp
Latest Disclosed Ownership	100,000 shares
Latest Disclosed Value	$ 2,016,000

On May 15, 2026 - Mendon Capital Advisors Corp filed a 13F-HR form disclosing ownership of 100,000 shares of Old Second Bancorp, Inc. (DE:OSB) valued at $1,710,000 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 18, 2026 disclosing 100,000 shares of Old Second Bancorp, Inc.. This represents a change in shares of 0.00% during the quarter. The current value of the position is $1,820,000 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)

File Date	Effective Date	Form	Security	Class	ID	Reported Shares	ΔShares	ΔShares (%)	Reported Value (x1000)	ΔValue (%)	Alloc (%)
2026-05-15	2026-03-31	13F	OLD SECOND BANCORP INC DEL	COM	680277100	100,000	0	0.00	2,016	3.38	0.7815
2026-02-18	2025-12-31	13F	OLD SECOND BANCORP INC ILL	COM	680277100	100,000	0	0.00	1,950	12.85	0.5776
2025-11-14	2025-09-30	13F	OLD SECOND BANCORP INC ILL	COM	680277100	100,000	0	0.00	1,728	-2.59	0.6630
2025-08-14	2025-06-30	13F	OLD SECOND BANCORP INC ILL	COM	680277100	100,000	0	0.00	1,774	6.61	0.8601
2025-05-21	2025-03-31	13F	OLD SECOND BANCORP INC ILL	COM	680277100	100,000	0	0.00	1,664	-6.41	0.7705
2025-02-14	2024-12-31	13F	OLD SECOND BANCORP INC ILL	COM	680277100	100,000	0	0.00	1,778	14.05	0.8755
2024-11-14	2024-09-30	13F	OLD SECOND BANCORP INC ILL	COM	680277100	100,000	-50,000	-33.33	1,559	-29.81	1.0059
2024-08-30	2024-06-30	13F	OLD SECOND BANCORP INC ILL	COM	680277100	150,000	0	0.00	2,222	6.98	1.2320
2024-05-15	2024-03-31	13F	OLD SECOND BANCORP INC ILL	COM	680277100	150,000	-50,000	-25.00	2,076	-32.77	1.1128
2024-02-23	2023-12-31	13F	OLD SECOND BANCORP INC ILL	COM	680277100	200,000	-220,732	-52.46	3,088	-49.42	1.2812
2022-05-16	2022-03-31	13F	OLD SECOND BANCORP ORD	COM	680277100	420,732	-29,968	-6.65	6,105	7.60	2.0215
2022-02-11	2021-12-31	13F	OLD SECOND BANCORP ORD	COM	680277100	450,700	250,700	125.35	5,674	117.23	1.6304
2021-11-09	2021-09-30	13F	OLD SECOND BANCORP ORD	COM	680277100	200,000	50,000	33.33	2,612	40.43	0.8900
2021-08-13	2021-06-30	13F	OLD SECOND BANCORP INCILL COM	COM	680277100	150,000	0	0.00	1,860	-6.11	0.6712
2021-05-11	2021-03-31	13F	OLD SECOND BANCORP ORD	COM	680277100	150,000	-10,000	-6.25	1,981	22.59	0.7294
2021-02-11	2020-12-31	13F	OLD SECOND BANCORP INC ILL	COM	680277100	160,000	6,629	4.32	1,616	40.52	0.7581
2020-11-10	2020-09-30	13F	OLD SECOND BANCORP INC ILL	COM	680277100	153,371	2,842	1.89	1,150	-1.79	0.6711
2020-08-05	2020-06-30	13F	OLD SECOND BANCORP INC ILL	COM	680277100	150,529	150,529		1,171		0.5960
2017-11-14	2017-09-30	13F	OLD SECOND BANCORP INC ILL	COM	680277100	0	-283,288	-100.00	0	-100.00
2017-08-14	2017-06-30	13F	OLD SECOND BANCORP INC ILL	COM	680277100	283,288	0	0.00	3,272	2.67	0.2601
2017-05-12	2017-03-31	13F	OLD SECOND BANCORP INC ILL	COM	680277100	283,288	0	0.00	3,187	1.82	0.2558
2017-02-13	2016-12-31	13F	OLD SECOND BANCORP INC ILL	COM	680277100	283,288	25,000	9.68	3,130	45.85	0.3216
2016-11-17	2016-09-30	13F/A-1	OLD SECOND BANCORP INC ILL	COM	680277100	258,288	0	0.00	2,146	21.66	0.2446
2016-08-03	2016-06-30	13F	OLD SECOND BANCORP INC ILL	COM	680277100	258,288	0	0.00	1,764	-4.75	0.1819
2016-05-09	2016-03-31	13F	OLD SECOND BANCORP INC ILL	COM	680277100	258,288	0	0.00	1,852	-8.54	0.2354
2016-02-12	2015-12-31	13F	OLD SECOND BANCORP INC-DEL	COM	680277100	258,288	258,288		2,025		0.2729

Legend

Shares: The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value: The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price: The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class: This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred

Allocation (%): The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation: The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%): The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis: The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss: This is the market value of the position as of the effective date minus the cost basis.