CoStar Group, Inc.
MX ˙ BMV ˙ US22160N1090
DETTE SYMBOL ER IKKE LÆNGERE AKTIVT
SecurityMX:CSGP / CoStar Group, Inc.
InstitutionRobeco Institutional Asset Management B.V.
Latest Disclosed Ownership46,018 shares
Latest Disclosed Value $ 1,856,366
Robeco Institutional Asset Management B.V. reports 32.48% decrease in ownership of CSGP / CoStar Group, Inc.

On April 21, 2026 - Robeco Institutional Asset Management B.V. filed a 13F-HR form disclosing ownership of 46,018 shares of CoStar Group, Inc. (MX:CSGP) valued at $1,856,366 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 23, 2026 disclosing 68,155 shares of CoStar Group, Inc.. This represents a change in shares of -32.48% 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)
2026-04-21 2026-03-31 13F COSTAR GROUP COM 22160N109 46,018 -22,137 -32.48 1,856 -59.49 0.0026
2026-01-23 2025-12-31 13F COSTAR GROUP COM 22160N109 68,155 -6,513 -8.72 4,583 -27.26 0.0065
2025-10-22 2025-09-30 13F COSTAR GROUP COM 22160N109 74,668 -7,916 -9.59 6,300 -5.12 0.0091
2025-07-18 2025-06-30 13F COSTAR GROUP COM 22160N109 82,584 -11,371 -12.10 6,640 -10.81 0.0107
2025-04-23 2025-03-31 13F COSTAR GROUP COM 22160N109 93,955 -25,503 -21.35 7,444 -12.95 0.0145
2025-01-23 2024-12-31 13F COSTAR GROUP COM 22160N109 119,458 -8,591 -6.71 8,552 -11.48 0.0162
2024-10-29 2024-09-30 13F COSTAR GROUP COM 22160N109 128,049 -178,421 -58.22 9,660 -57.48 0.0192
2024-07-23 2024-06-30 13F COSTAR GROUP COM 22160N109 306,470 263,193 608.16 22,722 443.56 0.0489
2024-04-24 2024-03-31 13F COSTAR GROUP COM 22160N109 43,277 -16,809 -27.97 4,181 -20.38 0.0091
2024-02-14 2023-12-31 13F/A-1 COSTAR GROUP COM 22160N109 60,086 -36,584 -37.84 5,251 -29.36 0.0127
2024-02-08 2023-12-31 13F COSTAR GROUP COM 22160N109 53,126 -43,544 60 0.0113
2023-10-24 2023-09-30 13F COSTAR GROUP COM 22160N109 96,670 23,374 31.89 7,433 13.94 0.0199
2023-07-24 2023-06-30 13F COSTAR GROUP COM 22160N109 73,296 387 0.53 6,523 29.97 0.0171
2023-05-04 2023-03-31 13F COSTAR GROUP COM 22160N109 72,909 -367,154 -83.43 5,020 -85.24 0.0137
2023-02-07 2022-12-31 13F COSTAR GROUP COM 22160N109 440,063 237,919 117.70 34,008 141.57 0.0980
2022-12-01 2022-09-30 13F/A-1 COSTAR GROUP COM 22160N109 202,144 100,162 98.22 14,078 128.50 0.0455
2022-10-27 2022-09-30 13F COSTAR GROUP COM 22160N109 202,144 100,162 14,078 0.0449
2022-12-01 2022-06-30 13F/A-1 COSTAR GROUP COM 22160N109 101,982 152 0.15 6,161 -9.17 0.0191
2022-07-27 2022-06-30 13F COSTAR GROUP COM 22160N109 101,982 152 6,161 0.0189
2022-12-01 2022-03-31 13F/A-1 COSTAR GROUP COM 22160N109 101,830 -199 -0.20 6,783 -15.86 0.0160
2022-04-26 2022-03-31 13F COSTAR GROUP COM 22160N109 101,830 -199 6,783 0.0158
2022-12-01 2021-12-31 13F/A-1 COSTAR GROUP COM 22160N109 102,029 92 0.09 8,062 -8.11 0.0172
2022-01-31 2021-12-31 13F COSTAR GROUP COM 22160N109 102,029 92 8,062 0.0169
2022-12-01 2021-09-30 13F/A-1 COSTAR GROUP COM 22160N109 101,937 -26,363 -20.55 8,774 -17.43 0.0195
2021-10-20 2021-09-30 13F COSTAR GROUP COM 22160N109 101,937 -26,363 8,774 0.0192
2022-12-01 2021-06-30 13F/A-1 COSTAR GROUP COM 22160N109 128,300 115,341 890.05 10,626 -0.24 0.0236
2021-07-28 2021-06-30 13F COSTAR GROUP COM 22160N109 128,300 115,341 10,626 0.0232
2022-12-01 2021-03-31 13F/A-1 COSTAR GROUP COM 22160N109 12,959 1,043 8.75 10,652 -3.28 0.0263
2021-04-23 2021-03-31 13F COSTAR GROUP COM 22160N109 12,959 1,043 10,652 0.0259
2022-12-01 2020-12-31 13F/A-1 COSTAR GROUP COM 22160N109 11,916 1,340 12.67 11,013 22.72 0.0289
2021-01-28 2020-12-31 13F COSTAR GROUP COM 22160N109 11,916 1,340 11,013 0.0286
2021-01-19 2020-09-30 13F/A-1 COSTAR GROUP COM 22160N109 10,576 -200 -1.86 8,974 17.18 0.0277
2020-10-29 2020-09-30 13F COSTAR GROUP COM 22160N109 10,576 -200 8,974 27,714.6327
2021-01-19 2020-06-30 13F/A-1 COSTAR GROUP COM 22160N109 10,776 -1,664 -13.38 7,658 4.83 0.0260
2020-07-20 2020-06-30 13F COSTAR GROUP COM 22160N109 10,776 -1,664 7,658 25,984.9599
2021-01-19 2020-03-31 13F/A-1 COSTAR GROUP COM 22160N109 12,440 -1,621 -11.53 7,305 -13.17 0.0293
2020-04-30 2020-03-31 13F COSTAR GROUP COM 22160N109 12,440 -1,621 7,305 29,280.0874
2021-01-19 2019-12-31 13F/A-1 COSTAR GROUP COM 22160N109 14,061 -8,282 -37.07 8,413 -36.52 0.0269
2020-02-06 2019-12-31 13F COSTAR GROUP COM 22160N109 14,061 -8,282 8,413 26,908.3335
2021-01-19 2019-09-30 13F/A-1 COSTAR GROUP COM 22160N109 22,343 2,556 12.92 13,254 20.88 0.0468
2019-10-17 2019-09-30 13F COSTAR GROUP COM 22160N109 22,343 2,556 13,254 46,725.8007
2021-01-19 2019-06-30 13F/A-1 COSTAR GROUP COM 22160N109 19,787 7,078 55.69 10,965 84.97 0.0387
2019-07-19 2019-06-30 13F COSTAR GROUP COM 22160N109 19,787 7,078 10,965 38,665.4581
2021-01-19 2019-03-31 13F/A-1 COSTAR GROUP COM 22160N109 12,709 340 2.75 5,928 42.12 0.0218
2019-05-02 2019-03-31 13F COSTAR GROUP COM 22160N109 12,709 340 5,928 21,765.5072
2021-01-19 2018-12-31 13F/A-1 COSTAR GROUP COM 22160N109 12,369 -1,528 -11.00 4,171 -28.69 0.0187
2019-02-08 2018-12-31 13F COSTAR GROUP COM 22160N109 12,369 -1,528 4,171 18,696.3008
2021-01-19 2018-09-30 13F/A-1 COSTAR GROUP COM 22160N109 13,897 3,017 27.73 5,849 30.33 0.0232
2018-10-25 2018-09-30 13F COSTAR GROUP COM 22160N109 13,897 3,017 5,849
2021-01-19 2018-06-30 13F/A-1 COSTAR GROUP COM 22160N109 10,880 -2,670 -19.70 4,488 -8.67 0.0204
2018-08-03 2018-06-30 13F COSTAR GROUP COM 22160N109 10,880 -2,670 4,488
2021-01-19 2018-03-31 13F/A-1 COSTAR GROUP COM 22160N109 13,550 -2,832 -17.29 4,914 1.03 0.0231
2018-05-07 2018-03-31 13F COSTAR GROUP COM 22160N109 13,550 -2,832 4,914 22,980.4793
2021-01-19 2017-12-31 13F/A-1 COSTAR GROUP COM 22160N109 16,382 15,603 2,002.95 4,864 2,216.19 0.0252
2018-01-25 2017-12-31 13F COSTAR GROUP COM 22160N109 16,382 15,603 4,864
2021-01-19 2017-09-30 13F/A-1 COSTAR GROUP COM 22160N109 779 273 53.95 210 56.72 0.0013
2017-10-17 2017-09-30 13F COSTAR GROUP COM 22160N109 779 273 210 1,301.0237
2021-01-19 2017-06-30 13F/A-1 COSTAR GROUP COM 22160N109 506 506 134 0.0009
2017-08-07 2017-06-30 13F COSTAR GROUP COM 22160N109 506 506 134 872.4479
2021-01-19 2017-03-31 13F/A-1 COSTAR GROUP COM 22160N109 0 -432 -100.00 0 -100.00
2017-02-09 2016-12-31 13F COSTAR GROUP COM 22160N109 432 432 82 0.0006
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.