Mainstream Capital Management’s Costco COST Stock Holding History

Mainstream 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 Q2	$2.17M	Sell	2,323 -5	-0.2%	-$4.98K	1.31%	21
2026 Q1	$2.32M	Buy	2,328 +1	+0%	+$975	1.56%	15
2025 Q4	$2.01M	Sell	2,327 -57	-2%	-$51.7K	1.31%	21
2025 Q3	$2.21M	Buy	2,384 +104	+5%	+$99.7K	1.47%	19
2025 Q2	$2.26M	Sell	2,280 -2	-0.1%	-$1.99K	1.64%	14
2025 Q1	$2.16M	Buy	2,282 +106	+5%	+$103K	1.71%	11
2024 Q4	$1.99M	Buy	2,176 +15	+0.7%	+$13.9K	1.4%	15
2024 Q3	$1.92M	Buy	+2,161	New	+$1.88M	1.63%	15

Other funds holding COST

Assenagon Asset Management Senningerberg, Luxembourg $80.2B AUM 50.57% 1-Year Est. Return

Swedbank Stockholm, Sweden $116B AUM 46.87% 1-Year Est. Return

Emerald Advisors Bellevue, Washington $796M AUM 2.51% 1-Year Est. Return

Robeco Institutional Asset Management Rotterdam, Netherlands $81.4B AUM 40.71% 1-Year Est. Return

Ninety One (UK) London, United Kingdom $44.7B AUM 17.24% 1-Year Est. Return

Sarasin & Partners London, United Kingdom $8.54B AUM 9.6% 1-Year Est. Return

CAM

Congress Asset Management Boston, Massachusetts $16.3B AUM 42.69% 1-Year Est. Return

CRM

Cardano Risk Management Rotterdam, Netherlands $13B AUM 49.44% 1-Year Est. Return

Steginsky Capital Port Washington, New York $666M AUM 34.57% 1-Year Est. Return

OIAM

OFI Invest Asset Management Paris, France $10B AUM 48.47% 1-Year Est. Return

Mainstream Capital Management's COST Position: Q2 2026 in Review

Mainstream Capital Management reduced its Costco (COST) stake by 0.21% in Q2 2026, selling an estimated $4.98K and leaving 2,323 shares worth $2.17M. The position accounts for 1.31% of the portfolio, ranked #21.

Mainstream Capital Management first reported a position in COST in Q3 2024 and has held it in 8 quarters since. The position peaked at $2.32M in Q1 2026. 945 funds tracked by Wall St. Rank hold COST as of Q2 2026.

Mainstream Capital Management held 2,323 shares of Costco worth $2.17M as of Q2 2026.
Mainstream Capital Management sold 5 Costco shares in Q2 2026, an estimated $4.98K.
Costco made up 1.31% of Mainstream Capital Management's portfolio in Q2 2026, its #21 holding.
Mainstream Capital Management first reported a position in Costco in Q3 2024 and has held it in 8 quarters since.
Mainstream Capital Management's Costco position peaked at $2.32M in Q1 2026.
945 funds tracked by Wall St. Rank held Costco as of Q2 2026.

Based on Mainstream Capital Management's 13F filing for Q2 2026, filed 15 Jul 2026.