CoStar Group, Inc.
MX ˙ BMV ˙ US22160N1090
DIESES SYMBOL IST NICHT MEHR AKTIV
SecurityMX:CSGP / CoStar Group, Inc.
InstitutionHarbor Advisors LLC
Latest Disclosed Ownership26,560 shares
Latest Disclosed Value $ 1,071,430
Harbor Advisors LLC ownership in CSGP / CoStar Group, Inc.

On May 7, 2026 - Harbor Advisors LLC filed a 13F-HR form disclosing ownership of 26,560 shares of CoStar Group, Inc. (MX:CSGP) valued at $1,071,430 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 30, 2026 disclosing 26,560 shares of CoStar Group, Inc.. This represents a change in shares of 0.00% during the quarter.

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)
2026-05-07 2026-03-31 13F COSTAR GROUP COM 22160N109 26,560 0 0.00 1,071 -40.00 0.1548
2026-01-30 2025-12-31 13F COSTAR GROUP COM 22160N109 26,560 4,000 17.73 1,786 -6.20 0.2682
2025-11-12 2025-09-30 13F COSTAR GROUP COM 22160N109 22,560 0 0.00 1,903 4.96 0.2936
2025-08-13 2025-06-30 13F COSTAR GROUP COM 22160N109 22,560 0 0.00 1,814 1.45 0.2968
2025-05-15 2025-03-31 13F COSTAR GROUP COM 22160N109 22,560 0 0.00 1,787 10.65 0.3103
2025-02-11 2024-12-31 13F COSTAR GROUP COM 22160N109 22,560 2,500 12.46 1,615 6.74 0.2537
2024-11-14 2024-09-30 13F COSTAR GROUP COM 22160N109 20,060 3,000 17.58 1,513 19.70 0.2533
2024-07-30 2024-06-30 13F COSTAR GROUP COM 22160N109 17,060 0 0.00 1,265 -23.25 0.2319
2024-05-01 2024-03-31 13F COSTAR GROUP COM 22160N109 17,060 0 0.00 1,648 10.54 0.3027
2024-02-01 2023-12-31 13F COSTAR GROUP COM 22160N109 17,060 7,000 69.58 1,491 92.76 0.2851
2023-11-07 2023-09-30 13F COSTAR GROUP COM 22160N109 10,060 0 0.00 774 -13.63 0.1657
2023-08-15 2023-06-30 13F/A-1 COSTAR GROUP COM 22160N109 10,060 0 0.00 895 29.34 0.1903
2023-08-01 2023-06-30 13F COSTAR GROUP COM 22160N109 10,060 895
2023-05-11 2023-03-31 13F COSTAR GROUP COM 22160N109 10,060 0 0.00 693 -10.94 0.1621
2023-02-13 2022-12-31 13F COSTAR GROUP COM 22160N109 10,060 0 0.00 777 10.84 0.1941
2022-11-07 2022-09-30 13F COSTAR GROUP COM 22160N109 10,060 0 0.00 701 15.30 0.1886
2022-08-05 2022-06-30 13F COSTAR GROUP COM 22160N109 10,060 0 0.00 608 -9.25 0.1476
2022-05-16 2022-03-31 13F COSTAR GROUP COM 22160N109 10,060 0 0.00 670 -15.72 0.1374
2022-02-14 2021-12-31 13F COSTAR GROUP COM 22160N109 10,060 0 0.00 795 -8.20 0.1479
2021-10-29 2021-09-30 13F COSTAR GROUP COM 22160N109 10,060 0 0.00 866 3.96 0.1732
2021-08-03 2021-06-30 13F COSTAR GROUP COM 22160N109 10,060 9,054 900.00 833 0.73 0.1647
2021-05-04 2021-03-31 13F COSTAR GROUP COM 22160N109 1,006 0 0.00 827 -11.08 0.1833
2021-02-11 2020-12-31 13F COSTAR GROUP COM 22160N109 1,006 0 0.00 930 8.90 0.2083
2020-11-09 2020-09-30 13F COSTAR GROUP COM 22160N109 1,006 0 0.00 854 19.44 0.2007
2020-08-03 2020-06-30 13F COSTAR GROUP COM 22160N109 1,006 0 0.00 715 20.98 0.1832
2020-05-21 2020-03-31 13F COSTAR GROUP COM 22160N109 1,006 0 0.00 591 -1.83 0.1793
2020-02-13 2019-12-31 13F COSTAR GROUP COM 22160N109 1,006 0 0.00 602 0.84 0.1631
2019-11-13 2019-09-30 13F COSTAR GROUP COM 22160N109 1,006 0 0.00 597 7.18 0.1708
2019-08-14 2019-06-30 13F COSTAR GROUP COM 22160N109 1,006 200 24.81 557 48.14 0.1665
2019-05-15 2019-03-31 13F COSTAR GROUP COM 22160N109 806 0 0.00 376 38.24 0.1212
2019-02-15 2018-12-31 13F COSTAR GROUP COM 22160N109 806 0 0.00 272 -19.76 0.1058
2018-11-14 2018-09-30 13F COSTAR GROUP COM 22160N109 806 0 0.00 339 1.80 0.1053
2018-08-07 2018-06-30 13F COSTAR GROUP COM 22160N109 806 0 0.00 333 14.04 0.1072
2018-05-11 2018-03-31 13F COSTAR GROUP COM 22160N109 806 806 292 0.0983
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.