MCM
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Mattern Capital Management’s Costco COST Stock Holding History

Mattern Capital Management’s Portfolio COST Stock Details COST Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q1 		$14.4M Sell
14,415
-171
-1% -$167K 1.72% 4
2025
Q4 		$12.6M Buy
14,586
+711
+5% +$644K 1.49% 8
2025
Q3 		$12.8M Sell
13,875
-243
-2% -$233K 1.51% 7
2025
Q2 		$14M Buy
14,118
+35
+0.2% +$34.8K 1.68% 5
2025
Q1 		$13.3M Sell
14,083
-1,066
-7% -$1.04M 1.7% 4
2024
Q4 		$13.9M Sell
15,149
-622
-4% -$577K 1.81% 3
2024
Q3 		$14M Sell
15,771
-163
-1% -$141K 1.76% 4
2024
Q2 		$13.5M Sell
15,934
-235
-1% -$183K 1.87% 3
2024
Q1 		$11.8M Sell
16,169
-685
-4% -$489K 1.61% 7
2023
Q4 		$11.1M Buy
16,854
+105
+0.6% +$62.2K 1.62% 6
2023
Q3 		$9.46M Buy
16,749
+738
+5% +$407K 1.53% 7
2023
Q2 		$8.62M Buy
16,011
+377
+2% +$191K 1.4% 7
2023
Q1 		$7.77M Buy
15,634
+360
+2% +$177K 1.37% 11
2022
Q4 		$6.97M Buy
15,274
+780
+5% +$381K 1.29% 16
2022
Q3 		$6.84M Sell
14,494
-284
-2% -$148K 1.43% 9
2022
Q2 		$7.08M Sell
14,778
-916
-6% -$465K 1.4% 8
2022
Q1 		$9.04M Buy
15,694
+76
+0.5% +$39.9K 1.62% 4
2021
Q4 		$8.87M Sell
15,618
-597
-4% -$306K 1.55% 4
2021
Q3 		$7.29M Buy
16,215
+109
+0.7% +$47.9K 1.44% 7
2021
Q2 		$6.37M Buy
16,106
+531
+3% +$201K 1.26% 26
2021
Q1 		$5.49M Buy
15,575
+850
+6% +$296K 1.19% 35
2020
Q4 		$5.55M Buy
14,725
+101
+0.7% +$37.7K 1.32% 24
2020
Q3 		$5.19M Buy
14,624
+68
+0.5% +$22.9K 1.36% 12
2020
Q2 		$4.41M Buy
14,556
+21
+0.1% +$6.39K 1.28% 25
2020
Q1 		$4.14M Sell
14,535
-571
-4% -$173K 1.41% 7
2019
Q4 		$4.44M Buy
+15,106
New +$4.49M 1.23% 23

Other funds holding COST

BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
Invesco
Invesco Atlanta, Georgia $1.02T AUM 30.18% 1-Year Est. Return
VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return
Morgan Stanley
Morgan Stanley New York $1.66T AUM 25.57% 1-Year Est. Return
Bank of America
Bank of America Charlotte, North Carolina $1.37T AUM 24.88% 1-Year Est. Return
DAM
Diamant Asset Management Ridgefield, Connecticut $137B AUM 18.02% 1-Year Est. Return
Fidelity Investments
Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return

Mattern Capital Management's COST Position: Q1 2026 in Review

Mattern Capital Management reduced its Costco (COST) stake by 1.2% in Q1 2026, selling an estimated $167K and leaving 14,415 shares worth $14.4M. The position accounts for 1.72% of the portfolio, ranked #4.

Mattern Capital Management first reported a position in COST in Q4 2019 and has held it in 26 quarters since. 4,236 funds tracked by Wall St. Rank hold COST as of Q1 2026.

  • Mattern Capital Management held 14,415 shares of Costco worth $14.4M as of Q1 2026.
  • Mattern Capital Management sold 171 Costco shares in Q1 2026, an estimated $167K.
  • Costco made up 1.72% of Mattern Capital Management's portfolio in Q1 2026, its #4 holding.
  • Mattern Capital Management first reported a position in Costco in Q4 2019 and has held it in 26 quarters since.
  • 4,236 funds tracked by Wall St. Rank held Costco as of Q1 2026.

Based on Mattern Capital Management's 13F filing for Q1 2026, filed 4 May 2026.