CoStar Group, Inc.
US ˙ NasdaqGS ˙ US22160N1090

SecurityCSGP / CoStar Group, Inc.
InstitutionSei Investments Co
Latest Disclosed Ownership621,779 shares
Latest Disclosed Value $ 41,809,182
Sei Investments Co reports 7.43% decrease in ownership of CSGP / CoStar Group, Inc.

On February 13, 2026 - Sei Investments Co filed a 13F-HR form disclosing ownership of 621,779 shares of CoStar Group, Inc. (US:CSGP) valued at $41,808,420 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 671,686 shares of CoStar Group, Inc.. This represents a change in shares of -7.43% during the quarter. The current value of the position is $20,767,419 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 Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-02-13 2025-12-31 13F COSTAR GROUP COM 22160N109 621,779 -49,907 -7.43 41,809 -26.22
2025-11-13 2025-09-30 13F COSTAR GROUP COM 22160N109 671,686 17,039 2.60 56,670 7.67 0.0609
2025-08-14 2025-06-30 13F COSTAR GROUP COM 22160N109 654,647 -26,238 -3.85 52,631 -2.44 0.0610
2025-05-14 2025-03-31 13F/A-1 COSTAR GROUP COM 22160N109 680,885 26,170 4.00 53,948 15.10 0.0694
2025-05-13 2025-03-31 13F COSTAR GROUP COM 22160N109 664,381 9,666 48,017 0.0522
2025-02-11 2024-12-31 13F COSTAR GROUP COM 22160N109 654,715 -525,849 -44.54 46,872 -47.37 0.0602
2024-11-12 2024-09-30 13F COSTAR GROUP COM 22160N109 1,180,564 -53,028 -4.30 89,062 -2.62 0.1157
2024-08-13 2024-06-30 13F COSTAR GROUP COM 22160N109 1,233,592 27,656 2.29 91,458 -21.49 0.1296
2024-05-07 2024-03-31 13F COSTAR GROUP COM 22160N109 1,205,936 58,489 5.10 116,494 16.18 0.1707
2024-02-14 2023-12-31 13F COSTAR GROUP COM 22160N109 1,147,447 -26,102 -2.22 100,275 11.13 0.1610
2023-11-14 2023-09-30 13F COSTAR GROUP COM 22160N109 1,173,549 25,879 2.25 90,234 -11.66 0.1621
2023-08-11 2023-06-30 13F COSTAR GROUP COM 22160N109 1,147,670 195,185 20.49 102,143 55.76 0.1782
2023-05-12 2023-03-31 13F COSTAR GROUP COM 22160N109 952,485 -127,023 -11.77 65,578 -21.39 0.1218
2023-02-10 2022-12-31 13F COSTAR GROUP COM 22160N109 1,079,508 289,864 36.71 83,424 51.68 0.1854
2022-11-14 2022-09-30 13F COSTAR GROUP COM 22160N109 789,644 -49,708 -5.92 55,000 8.52 0.1227
2022-08-15 2022-06-30 13F COSTAR GROUP COM 22160N109 839,352 43,264 5.43 50,684 -4.35 0.1095
2022-05-13 2022-03-31 13F COSTAR GROUP COM 22160N109 796,088 -97,745 -10.94 52,989 -25.05 0.1065
2022-02-14 2021-12-31 13F COSTAR GROUP COM 22160N109 893,833 136,486 18.02 70,701 8.16 0.1326
2021-11-12 2021-09-30 13F COSTAR GROUP COM 22160N109 757,347 176,452 30.38 65,367 35.29 0.1371
2021-08-06 2021-06-30 13F COSTAR GROUP COM 22160N109 580,895 530,145 1,044.62 48,315 12.07 0.1071
2021-05-12 2021-03-31 13F COSTAR GROUP COM 22160N109 50,750 5,380 11.86 43,111 1.85 0.1086
2021-02-08 2020-12-31 13F COSTAR GROUP COM 22160N109 45,370 1,981 4.57 42,328 13.92 0.1094
2020-12-04 2020-09-30 13F/A-1 COSTAR GROUP COM 22160N109 43,389 -4,328 -9.07 37,157 9.93 0.1076
2020-11-06 2020-09-30 13F COSTAR GROUP COM 22160N109 46,288 -1,429 39,617 95,388.9276
2020-08-17 2020-06-30 13F/A-1 COSTAR GROUP COM 22160N109 47,717 -6,411 -11.84 33,801 5.75 0.1049
2020-08-11 2020-06-30 13F COSTAR GROUP COM 22160N109 57,687 3,559 35,731 96,922.2395
2020-05-14 2020-03-31 13F COSTAR GROUP COM 22160N109 54,128 1,988 3.81 31,963 2.40 0.1174
2020-02-06 2019-12-31 13F COSTAR GROUP COM 22160N109 52,140 -660 -1.25 31,214 -0.46 0.0931
2019-11-12 2019-09-30 13F COSTAR GROUP COM 22160N109 52,800 -4,210 -7.38 31,358 -0.87 0.0802
2019-08-14 2019-06-30 13F COSTAR GROUP COM 22160N109 57,010 1,608 2.90 31,634 22.66 0.1033
2019-05-15 2019-03-31 13F COSTAR GROUP COM 22160N109 55,402 -10,188 -15.53 25,790 -4.60 0.0866
2019-02-13 2018-12-31 13F COSTAR GROUP COM 22160N109 65,590 4,128 6.72 27,033 4.44 0.0962
2018-11-08 2018-09-30 13F COSTAR GROUP COM 22160N109 61,462 2,537 4.31 25,883 6.45 0.0938
2018-08-03 2018-06-30 13F COSTAR GROUP COM 22160N109 58,925 -2,732 -4.43 24,315 8.73 0.0826
2018-05-11 2018-03-31 13F COSTAR GROUP COM 22160N109 61,657 -19,506 -24.03 22,363 -7.22 0.0857
2018-02-08 2017-12-31 13F COSTAR GROUP COM 22160N109 81,163 -3,032 -3.60 24,102 6.71 0.0837
2017-11-06 2017-09-30 13F COSTAR GROUP COM 22160N109 84,195 -22,191 -20.86 22,586 -19.46 0.0803
2017-07-31 2017-06-30 13F COSTAR GROUP COM 22160N109 106,386 -7,645 -6.70 28,044 18.68 0.1118
2017-05-05 2017-03-31 13F COSTAR GROUP COM 22160N109 114,031 972 0.86 23,629 10.88 0.1035
2017-02-02 2016-12-31 13F COSTAR GROUP COM 22160N109 113,059 10,933 10.71 21,310 -3.63 0.1032
2016-11-04 2016-09-30 13F COSTAR GROUP COM 22160N109 102,126 -8,234 -7.46 22,113 -8.36 0.1123
2016-08-11 2016-06-30 13F COSTAR GROUP COM 22160N109 110,360 -13,236 -10.71 24,131 3.76 0.1447
2016-05-10 2016-03-31 13F/A-1 COSTAR GROUP COM 22160N109 123,596 9,219 8.06 23,256 -1.63 0.1447
2016-02-03 2015-12-31 13F COSTAR GROUP COM 22160N109 114,377 65,506 134.04 23,641 179.54 0.1441
2015-11-02 2015-09-30 13F/A-1 COSTAR GROUP COM 22160N109 48,871 -7,329 -13.04 8,457 -25.23 0.0776
2015-10-30 2015-09-30 13F COSTAR GROUP COM 22160N109 48,871 8,459
2015-08-07 2015-06-30 13F/A-1 COSTAR GROUP COM 22160N109 56,200 -312 -0.55 11,310 1.17 0.1022
2015-08-04 2015-06-30 13F COSTAR GROUP COM 22160N109 56,200 -312 11,310 0.1022
2015-05-14 2015-03-31 13F/A-1 COSTAR GROUP COM 22160N109 56,512 -1,330 -2.30 11,179 5.25 0.0971
2015-05-01 2015-03-31 13F COSTAR GROUP COM 22160N109 56,512 11,179
2015-02-10 2014-12-31 13F COSTAR GROUP COM 22160N109 57,842 57,842 10,621 0.0939
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.