CoStar Group, Inc.
MX ˙ BMV ˙ US22160N1090
DETTE SYMBOL ER IKKE LÆNGERE AKTIVT
SecurityMX:CSGP / CoStar Group, Inc.
InstitutionHarbor Investment Advisory, Llc
Latest Disclosed Ownership4,295 shares
Latest Disclosed Value $ 173,260
Harbor Investment Advisory, Llc reports 30.45% decrease in ownership of CSGP / CoStar Group, Inc.

On April 23, 2026 - Harbor Investment Advisory, Llc filed a 13F-HR form disclosing ownership of 4,295 shares of CoStar Group, Inc. (MX:CSGP) valued at $173,260 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 7, 2026 disclosing 6,175 shares of CoStar Group, Inc.. This represents a change in shares of -30.45% 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)
2026-04-23 2026-03-31 13F COSTAR GROUP INC COM Stock 22160N109 4,295 -1,880 -30.45 173 -58.31 0.0136
2026-01-07 2025-12-31 13F COSTAR GROUP INC COM Stock 22160N109 6,175 75 1.23 415 -19.26 0.0312
2025-10-27 2025-09-30 13F COSTAR GROUP INC COM Stock 22160N109 6,100 0 0.00 515 4.90 0.0425
2025-07-01 2025-06-30 13F COSTAR GROUP INC COM Stock 22160N109 6,100 -68 -1.10 490 0.41 0.0437
2025-04-09 2025-03-31 13F COSTAR GROUP INC COM Stock 22160N109 6,168 5,226 554.78 489 628.36 0.0475
2025-01-16 2024-12-31 13F COSTAR GROUP INC COM Stock 22160N109 942 -215 -18.58 67 -22.99 0.0063
2024-10-04 2024-09-30 13F COSTAR GROUP INC COM Stock 22160N109 1,157 -4 -0.34 87 1.16 0.0086
2024-07-19 2024-06-30 13F COSTAR GROUP INC COM Stock 22160N109 1,161 392 50.98 86 16.22 0.0090
2024-04-12 2024-03-31 13F COSTAR GROUP INC COM Stock 22160N109 769 -8 -1.03 74 10.45 0.0078
2024-01-26 2023-12-31 13F COSTAR GROUP INC COM Stock 22160N109 777 31 4.16 68 17.54 0.0078
2023-10-13 2023-09-30 13F COSTAR GROUP INC COM Stock 22160N109 746 0 0.00 57 -13.64 0.0075
2023-07-14 2023-06-30 13F COSTAR GROUP INC COM Stock 22160N109 746 -13 -1.71 66 26.92 0.0092
2023-04-21 2023-03-31 13F COSTAR GROUP INC COM Stock 22160N109 759 -110 -12.66 52 -22.39 0.0078
2023-01-24 2022-12-31 13F COSTAR GROUP INC COM Stock 22160N109 869 -147 -14.47 67 -5.63 0.0105
2022-11-01 2022-09-30 13F COSTAR GROUP INC COM Stock 22160N109 1,016 285 38.99 71 61.36 0.0117
2022-07-18 2022-06-30 13F COSTAR GROUP INC COM Stock 22160N109 731 231 46.20 44 33.33 0.0071
2022-04-20 2022-03-31 13F COSTAR GROUP INC COM Stock 22160N109 500 0 0.00 33 -17.50 0.0044
2022-01-10 2021-12-31 13F COSTAR GROUP INC COM Stock 22160N109 500 -327 -39.54 40 -43.66 0.0051
2021-10-12 2021-09-30 13F COSTAR GROUP INC COM Stock 22160N109 827 327 65.40 71 73.17 0.0096
2021-07-27 2021-06-30 13F COSTAR GROUP INC COM Stock 22160N109 500 450 900.00 41 0.00 0.0056
2021-04-16 2021-03-31 13F COSTAR GROUP INC COM Stock 22160N109 50 0 0.00 41 -10.87 0.0062
2021-02-04 2020-12-31 13F COSTAR GROUP INC COM Stock 22160N109 50 0 0.00 46 9.52 0.0074
2020-10-23 2020-09-30 13F COSTAR GROUP INC COM Stock 22160N109 50 0 0.00 42 16.67 0.0080
2020-07-16 2020-06-30 13F COSTAR GROUP INC COM Stock 22160N109 50 0 0.00 36 24.14 0.0076
2020-05-11 2020-03-31 13F COSTAR GROUP INC COM Stock 22160N109 50 0 0.00 29 -3.33 0.0078
2020-01-16 2019-12-31 13F COSTAR GROUP INC COM Stock 22160N109 50 50 30 0.0069
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.