Mattern Capital Management
COST icon

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
Q3 		$13.1M Sell
14,356
-16
-0.1% -$14.9K 1.53% 5
2026
Q2 		$13.4M Sell
14,372
-43
-0.3% -$42.8K 1.57% 5
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

Bank of New York Mellon
Bank of New York Mellon New York $608B AUM 32.77% 1-Year Est. Return
Dimensional Fund Advisors
Dimensional Fund Advisors Austin, Texas $551B AUM 33.95% 1-Year Est. Return
Mitsubishi UFJ Asset Management
Mitsubishi UFJ Asset Management Tokyo, Japan $194B AUM 32.2% 1-Year Est. Return
Principal Financial Group
Principal Financial Group Des Moines, Iowa $195B AUM 21.17% 1-Year Est. Return
Sumitomo Mitsui Trust Group
Sumitomo Mitsui Trust Group Minato-Ku, Tokyo, Japan $174B AUM 33.96% 1-Year Est. Return
Citigroup
Citigroup New York $308B AUM 40.94% 1-Year Est. Return
Everett Harris & Co
Everett Harris & Co Los Angeles, California $8.46B AUM 13.48% 1-Year Est. Return
Swedbank
Swedbank Stockholm, Sweden $118B AUM 40.52% 1-Year Est. Return
Emerald Advisors
Emerald Advisors Bellevue, Washington $781M AUM 4.78% 1-Year Est. Return
Parnassus Investments
Parnassus Investments San Francisco, California $33.8B AUM 31.08% 1-Year Est. Return

Mattern Capital Management's COST Position: Q3 2026 in Review

Mattern Capital Management reduced its Costco (COST) stake by 0.11% in Q3 2026, selling an estimated $14.9K and leaving 14,356 shares worth $13.1M. The position accounts for 1.53% of the portfolio, ranked #5.

Mattern Capital Management first reported a position in COST in Q4 2019 and has held it in 28 quarters since. The position peaked at $14.4M in Q1 2026. 2,489 funds tracked by Wall St. Rank hold COST as of Q3 2026.

  • Mattern Capital Management held 14,356 shares of Costco worth $13.1M as of Q3 2026.
  • Mattern Capital Management sold 16 Costco shares in Q3 2026, an estimated $14.9K.
  • Costco made up 1.53% of Mattern Capital Management's portfolio in Q3 2026, its #5 holding.
  • Mattern Capital Management first reported a position in Costco in Q4 2019 and has held it in 28 quarters since.
  • Mattern Capital Management's Costco position peaked at $14.4M in Q1 2026.
  • 2,489 funds tracked by Wall St. Rank held Costco as of Q3 2026.

Based on Mattern Capital Management's 13F filing for Q3 2026, filed 2 Nov 2026.