William Blair Investment Management, LLC / COST
William Blair Investment Management, LLC’s Costco Wholesale Corporation Position
Does William Blair Investment Management, LLC own Costco Wholesale Corporation (COST)? Yes — 302.5K shares worth $301M (+1.00% of its 13F portfolio) as of Q1 2026, down from 328.5K shares the prior filed quarter.
Position Value
$301M
Q1 2026
Shares
302.5K
% of Portfolio
+1.00%
Quarters Held
30
currently held
Position History COST
Reported value by quarter
| Quarter | Shares | Value | % of Portfolio |
|---|---|---|---|
| Q1 2026 | 302.5K | $301M | +1.00% |
| Q4 2025 | 328.5K | $283M | +0.79% |
| Q3 2025 | 322.7K | $299M | +0.77% |
| Q2 2025 | 376.5K | $373M | +0.99% |
| Q1 2025 | 353.6K | $334M | +0.94% |
| Q4 2024 | 337.2K | $309M | +0.75% |
| Q3 2024 | 341.9K | $303M | +0.75% |
| Q2 2024 | 366.1K | $311M | +0.82% |
| Q1 2024 | 356.4K | $261M | +0.67% |
| Q4 2023 | 394.2K | $260M | +0.76% |
| Q3 2023 | 437.5K | $247M | +0.82% |
| Q2 2023 | 374.7K | $202M | +0.65% |
| Q1 2023 | 361.5K | $180M | +0.63% |
| Q4 2022 | 485.2K | $221M | +0.85% |
| Q3 2022 | 462.2K | $218M | +0.86% |
| Q2 2022 | 432.9K | $208M | +0.77% |
| Q1 2022 | 338.5K | $195M | +0.58% |
| Q4 2021 | 308.9K | $175M | +0.47% |
| Q3 2021 | 214.4K | $96M | +0.27% |
| Q2 2021 | 218.5K | $86M | +0.27% |
| Q1 2021 | 215.6K | $76M | +0.25% |
| Q4 2020 | 179.6K | $68M | +0.23% |
| Q3 2020 | 229.0K | $81M | +0.32% |
| Q2 2020 | 135.2K | $41M | +0.17% |
| Q1 2020 | 124.6K | $36M | +0.17% |
| Q4 2019 | 126.2K | $37M | +0.15% |
| Q3 2019 | 135.2K | $39M | +0.17% |
| Q2 2019 | 150.2K | $40M | +0.17% |
| Q1 2019 | 127.7K | $31M | +0.13% |
| Q4 2018 | 65.2K | $13M | +0.07% |
Common-stock position only; options are excluded. Quarters where the fund filed no 13F or reported no position are absent. See William Blair Investment Management, LLC’s full portfolio or all institutional holders of COST.