CoStar Group, Inc.
US ˙ NasdaqGS ˙ US22160N1090

SecurityCSGP / CoStar Group, Inc.
InstitutionChicago Capital, LLC
Latest Disclosed Ownership1,055,620 shares
Latest Disclosed Value $ 42,583,719
Chicago Capital, LLC reports 27.63% increase in ownership of CSGP / CoStar Group, Inc.

On April 23, 2026 - Chicago Capital, LLC filed a 13F-HR form disclosing ownership of 1,055,620 shares of CoStar Group, Inc. (US:CSGP) valued at $42,583,711 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 26, 2026 disclosing 827,123 shares of CoStar Group, Inc.. This represents a change in shares of 27.63% during the quarter. The current value of the position is $35,257,708 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)
2026-04-23 2026-03-31 13F COSTAR GROUP COM 22160N109 1,055,620 228,497 27.63 42,584 -23.43 1.1482
2026-01-26 2025-12-31 13F COSTAR GROUP COM 22160N109 827,123 -132,919 -13.85 55,616 -31.34 1.3736
2025-10-22 2025-09-30 13F COSTAR GROUP COM 22160N109 960,042 -4,248 -0.44 80,999 4.48 1.9933
2025-07-17 2025-06-30 13F COSTAR GROUP COM 22160N109 964,290 20,335 2.15 77,529 3.66 1.9133
2025-04-17 2025-03-31 13F COSTAR GROUP COM 22160N109 943,955 29,016 3.17 74,790 14.18 2.1122
2025-01-24 2024-12-31 13F COSTAR GROUP COM 22160N109 914,939 -6,400 -0.69 65,500 -5.76 1.7367
2024-10-18 2024-09-30 13F COSTAR GROUP COM 22160N109 921,339 9,155 1.00 69,506 2.77 1.9302
2024-08-06 2024-06-30 13F COSTAR GROUP COM 22160N109 912,184 -486 -0.05 67,629 -23.29 2.0106
2024-04-15 2024-03-31 13F COSTAR GROUP COM 22160N109 912,670 -2,128 -0.23 88,164 10.28 2.6866
2024-01-22 2023-12-31 13F COSTAR GROUP COM 22160N109 914,798 -3,085 -0.34 79,944 13.27 2.8787
2023-10-25 2023-09-30 13F COSTAR GROUP COM 22160N109 917,883 -2,422 -0.26 70,576 -13.83 3.3011
2023-07-20 2023-06-30 13F COSTAR GROUP COM 22160N109 920,305 -4,531 -0.49 81,907 28.63 3.6927
2023-04-18 2023-03-31 13F COSTAR GROUP COM 22160N109 924,836 90,135 10.80 63,675 -1.29 3.1681
2023-01-20 2022-12-31 13F COSTAR GROUP COM 22160N109 834,701 -1,961 -0.23 64,506 10.69 3.5684
2022-10-14 2022-09-30 13F COSTAR GROUP COM 22160N109 836,662 -1,136 -0.14 58,274 15.14 3.3704
2022-07-21 2022-06-30 13F COSTAR GROUP COM 22160N109 837,798 373,976 80.63 50,611 63.82 2.7960
2022-04-21 2022-03-31 13F COSTAR GROUP COM 22160N109 463,822 6,686 1.46 30,895 -14.48 1.3298
2022-01-20 2021-12-31 13F COSTAR GROUP COM 22160N109 457,136 -11,968 -2.55 36,127 -10.51 1.3453
2021-10-28 2021-09-30 13F COSTAR GROUP COM 22160N109 469,104 -3,284 -0.70 40,371 3.19 1.5312
2021-07-22 2021-06-30 13F COSTAR GROUP COM 22160N109 472,388 424,925 895.28 39,123 0.29 1.5289
2021-04-13 2021-03-31 13F COSTAR GROUP COM 22160N109 47,463 -688 -1.43 39,010 -12.35 1.6465
2021-01-25 2020-12-31 13F COSTAR GROUP COM 22160N109 48,151 -320 -0.66 44,505 8.21 1.9881
2020-10-13 2020-09-30 13F COSTAR GROUP COM 22160N109 48,471 -158 -0.32 41,128 19.01 2.1145
2020-07-29 2020-06-30 13F COSTAR GROUP COM 22160N109 48,629 191 0.39 34,559 21.50 2.0027
2020-04-21 2020-03-31 13F COSTAR GROUP COM 22160N109 48,438 -1,689 -3.37 28,443 -5.16 2.2936
2020-01-14 2019-12-31 13F COSTAR GROUP COM 22160N109 50,127 -27 -0.05 29,991 0.81 1.8298
2019-10-28 2019-09-30 13F COSTAR GROUP COMMON 22160N109 50,154 -22,457 -30.93 29,751 -26.05 1.9926
2019-07-11 2019-06-30 13F COSTAR GROUP COMMON 22160N109 72,611 -12,051 -14.23 40,231 1.88 2.5736
2019-04-23 2019-03-31 13F COSTAR GROUP COMMON 22160N109 84,662 7,192 9.28 39,488 51.10 2.6841
2019-02-11 2018-12-31 13F COSTAR GROUP COM 22160N109 77,470 -397 -0.51 26,134 -20.25 2.1311
2018-11-02 2018-09-30 13F COSTAR GROUP COM 22160N109 77,867 3,934 5.32 32,770 7.42 2.2670
2018-07-19 2018-06-30 13F COSTAR GROUP COM 22160N109 73,933 21,098 39.93 30,507 59.21 2.4595
2018-05-09 2018-03-31 13F Costar Group COM 22160N109 52,835 52,835 19,162 2.5569
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.