CoStar Group, Inc.
MX ˙ BMV ˙ US22160N1090
DETTE SYMBOL ER IKKE LÆNGERE AKTIVT
SecurityMX:CSGP / CoStar Group, Inc.
InstitutionBrown Brothers Harriman & Co
Latest Disclosed Ownership7,438 shares
Latest Disclosed Value $ 300,049
Brown Brothers Harriman & Co reports 609.73% increase in ownership of CSGP / CoStar Group, Inc.

On May 14, 2026 - Brown Brothers Harriman & Co filed a 13F-HR form disclosing ownership of 7,438 shares of CoStar Group, Inc. (MX:CSGP) valued at $300,049 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 1,048 shares of CoStar Group, Inc.. This represents a change in shares of 609.73% 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)
2026-05-14 2026-03-31 13F COSTAR GROUP Common Stock 22160N109 7,438 6,390 609.73 300 328.57 0.0016
2026-02-12 2025-12-31 13F COSTAR GROUP Common Stock 22160N109 1,048 -766 -42.23 70 -54.25 0.0004
2025-11-13 2025-09-30 13F COSTAR GROUP Common Stock 22160N109 1,814 684 60.53 153 70.00 0.0009
2025-08-11 2025-06-30 13F COSTAR GROUP Common Stock 22160N109 1,130 753 199.73 91 210.34 0.0006
2025-05-14 2025-03-31 13F COSTAR GROUP Common Stock 22160N109 377 278 280.81 30 314.29 0.0002
2025-02-12 2024-12-31 13F COSTAR GROUP Common Stock 22160N109 99 -281 -73.95 7 -75.00 0.0000
2024-11-13 2024-09-30 13F COSTAR GROUP Common Stock 22160N109 380 -7,300 -95.05 29 -95.08 0.0002
2024-08-09 2024-06-30 13F COSTAR GROUP Common Stock 22160N109 7,680 -357 -4.44 569 -26.68 0.0043
2024-05-10 2024-03-31 13F COSTAR GROUP Common Stock 22160N109 8,037 -5,867 -42.20 776 -36.13 0.0060
2024-02-12 2023-12-31 13F COSTAR GROUP Common Stock 22160N109 13,904 95 0.69 1,215 14.51 0.0101
2023-11-13 2023-09-30 13F COSTAR GROUP Common Stock 22160N109 13,809 329 2.44 1,062 -11.51 0.0094
2023-08-07 2023-06-30 13F COSTAR GROUP Common Stock 22160N109 13,480 0 0.00 1,200 29.20 0.0097
2023-05-11 2023-03-31 13F COSTAR GROUP Common Stock 22160N109 13,480 0 0.00 928 -10.85 0.0078
2023-02-09 2022-12-31 13F COSTAR GROUP Common Stock 22160N109 13,480 -5,020 -27.14 1,042 -19.24 0.0091
2022-11-14 2022-09-30 13F COSTAR GROUP Common Stock 22160N109 18,500 295 1.62 1,289 17.18 0.0119
2022-08-11 2022-06-30 13F COSTAR GROUP Common Stock 22160N109 18,205 -75 -0.41 1,100 -9.69 0.0094
2022-05-13 2022-03-31 13F COSTAR GROUP Common Stock 22160N109 18,280 1,750 10.59 1,218 -6.74 0.0086
2022-02-14 2021-12-31 13F COSTAR GROUP Common Stock 22160N109 16,530 2,900 21.28 1,306 11.34 0.0073
2021-11-15 2021-09-30 13F COSTAR GROUP Common Stock 22160N109 13,630 0 0.00 1,173 3.90 0.0069
2021-08-13 2021-06-30 13F COSTAR GROUP Common Stock 22160N109 13,630 12,241 881.28 1,129 -1.14 0.0067
2021-05-13 2021-03-31 13F COSTAR GROUP Common Stock 22160N109 1,389 26 1.91 1,142 -9.37 0.0073
2021-02-16 2020-12-31 13F COSTAR GROUP Common Stock 22160N109 1,363 0 0.00 1,260 8.90 0.0084
2020-11-16 2020-09-30 13F COSTAR GROUP Common Stock 22160N109 1,363 0 0.00 1,157 19.40 0.0083
2020-08-13 2020-06-30 13F COSTAR GROUP Common Stock 22160N109 1,363 -311 -18.58 969 -1.42 0.0073
2020-05-15 2020-03-31 13F COSTAR GROUP Common Stock 22160N109 1,674 15 0.90 983 -1.01 0.0080
2020-02-14 2019-12-31 13F COSTAR GROUP Common Stock 22160N109 1,659 0 0.00 993 0.91 0.0063
2019-11-14 2019-09-30 13F COSTAR GROUP Common Stock 22160N109 1,659 -1,090 -39.65 984 -35.39 0.0066
2019-08-14 2019-06-30 13F COSTAR GROUP Common Stock 22160N109 2,749 -2 -0.07 1,523 18.71 0.0101
2019-05-15 2019-03-31 13F COSTAR GROUP Common Stock 22160N109 2,751 4 0.15 1,283 38.40 0.0088
2019-02-14 2018-12-31 13F COSTAR GROUP Common Stock 22160N109 2,747 20 0.73 927 -19.25 0.0070
2018-11-14 2018-09-30 13F COSTAR GROUP Common Stock 22160N109 2,727 -956 -25.96 1,148 -24.47 0.0073
2018-08-14 2018-06-30 13F COSTAR GROUP Common Stock 22160N109 3,683 0 0.00 1,520 13.77 0.0093
2018-05-14 2018-03-31 13F COSTAR GROUP Common Stock 22160N109 3,683 -25 -0.67 1,336 21.34 0.0077
2018-02-14 2017-12-31 13F COSTAR GROUP Common Stock 22160N109 3,708 25 0.68 1,101 11.44 0.0061
2017-11-14 2017-09-30 13F COSTAR GROUP Common Stock 22160N109 3,683 157 4.45 988 6.35 0.0053
2017-08-14 2017-06-30 13F COSTAR GROUP Common Stock 22160N109 3,526 0 0.00 929 27.09 0.0050
2017-05-12 2017-03-31 13F COSTAR GROUP Common Stock 22160N109 3,526 2,466 232.64 731 265.50 0.0040
2017-02-14 2016-12-31 13F COSTAR GROUP Common Stock 22160N109 1,060 1,060 0.00 200 0.0011
2016-02-12 2015-12-31 13F COSTAR GROUP INC COM STK Common Stock 22160N109 0 -130 -100.00 0 -100.00
2015-11-13 2015-09-30 13F COSTAR GROUP INC COM STK Common Stock 22160N109 130 0 0.00 22 -15.38 0.0001
2015-08-14 2015-06-30 13F COSTAR GROUP INC COM STK Common Stock 22160N109 130 130 26 0.0001
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.