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Mattern Capital Management’s CoStar Group CSGP Stock Holding History

Mattern Capital Management’s Portfolio CSGP Stock Details CSGP Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q2 		$806K Buy
28,450
+8,705
+44% +$299K 0.09% 124
2026
Q1 		$797K Buy
19,745
+3,282
+20% +$171K 0.1% 120
2025
Q4 		$1.11M Buy
16,463
+3,266
+25% +$231K 0.13% 113
2025
Q3 		$1.11M Buy
13,197
+2,134
+19% +$189K 0.13% 113
2025
Q2 		$889K Buy
11,063
+1,173
+12% +$91.4K 0.11% 115
2025
Q1 		$784K Buy
9,890
+1,012
+11% +$77K 0.1% 112
2024
Q4 		$636K Buy
8,878
+1,188
+15% +$89.7K 0.08% 112
2024
Q3 		$580K Buy
7,690
+1,541
+25% +$117K 0.07% 108
2024
Q2 		$456K Buy
6,149
+1,751
+40% +$148K 0.06% 117
2024
Q1 		$425K Buy
+4,398
New +$379K 0.06% 118

Other funds holding CSGP

Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
BAMCO Inc
BAMCO Inc New York $66.6B AUM 7.35% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return
Capital International Investors
Capital International Investors Los Angeles, California $484B AUM 34.9% 1-Year Est. Return
Baillie Gifford & Co
Baillie Gifford & Co Edinburgh, United Kingdom $110B AUM 4.8% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return
ACM
AKRE Capital Management Middleburg, Virginia $5.12B AUM 19.08% 1-Year Est. Return
Polen Capital Management
Polen Capital Management Boca Raton, Florida $11.6B AUM 8.03% 1-Year Est. Return

Mattern Capital Management's CSGP Position: Q2 2026 in Review

Mattern Capital Management increased its CoStar Group (CSGP) stake by 44% in Q2 2026, buying an estimated $299K and bringing the position to 28,450 shares worth $806K. The position accounts for 0.09% of the portfolio, ranked #124.

Mattern Capital Management first reported a position in CSGP in Q1 2024 and has held it in 10 quarters since. The position peaked at $1.11M in Q3 2025. 757 funds tracked by Wall St. Rank hold CSGP as of Q2 2026.

  • Mattern Capital Management held 28,450 shares of CoStar Group worth $806K as of Q2 2026.
  • Mattern Capital Management bought 8,705 CoStar Group shares in Q2 2026, an estimated $299K.
  • CoStar Group made up 0.09% of Mattern Capital Management's portfolio in Q2 2026, its #124 holding.
  • Mattern Capital Management first reported a position in CoStar Group in Q1 2024 and has held it in 10 quarters since.
  • Mattern Capital Management's CoStar Group position peaked at $1.11M in Q3 2025.
  • 757 funds tracked by Wall St. Rank held CoStar Group as of Q2 2026.

Based on Mattern Capital Management's 13F filing for Q2 2026, filed 24 Jul 2026.