NASDAQ · Consumer Defensive · Holders
Costco Wholesale (COST) Institutional Ownership & Insider Trading History
Top COST institutional shareholders, filing changes, and Form 4 insider activity with filters for buys, sales, option exercises, gifts, and tax withholding.
- Last confirmed price
- $920.65+0.62%
- Oct 2, 2026, 4:00 PM EDT · Prices may be delayed
Data dates
Prices as of Oct 2, 4:00 PM EDT · Fundamentals checked Oct 4, 9:42 PM EDT · Statement period ended May 10, 2026
Ownership read
COST insider transaction activity: Net selling.
Blackrock Inc. is the largest institutional holder. 29 sales and 0 purchases appear in the recent Form 4 filings. Use the filters below to separate open-market activity from option exercises, gifts, awards, and tax withholding.
Insider flow
COST
Directional bars ignore awards, gifts, conversions, and tax withholding rows.
Top holder
34.20M
Blackrock Inc.
Insider transaction activity
Net selling
$49.42M sold / $0.0000 bought
Observations shown
94
10 holder / 84 insider
- Holder rows
- 10
- Yahoo Finance · Filing dates shown per row
- Increased / initiated
- 5
- 5 decreased · provider-reported changes
- Insider rows
- 84
- Yahoo Finance · Filing dates shown per row
Ownership concentration and transaction activity
- Top 10 reported holders
- 33.07% outstanding
- Changes with share-count history
- Prior-position data unavailable
- New / exited positions
- 0 / 0 explicitly reported
- Largest increase with share-count history
- Prior share counts unavailable
These changes cover the holders shown. A holder missing from this list may still own shares. Compare positions from the same reporting quarters.
Net shares sold: 52,703
Sale-code S shares minus purchase-code P shares in this sample. Includes disclosed plans and unknown plan status; excludes grants, gifts, exercises and withholding. This is activity, not sentiment.
- Purchase / sale; plan unknown: 29
- Grant: 43
- Gift: 12
Top 10 institutional holders
Costco Wholesale (COST) institutional ownership
Ranked by reported share count, with position changes and separate position and filing dates where ownership data supplies them.
| # | Institution | % held | Shares | Change % | Position / filing date |
|---|---|---|---|---|---|
| 1 | 7.71% | 34.20M | -2.13% | Position as of Jun 30, 2026Filing date unknown | |
| 2 | 6.53% | 28.98M | +0.45% | Position as of Jun 30, 2026Filing date unknown | |
| 3 | 4.15% | 18.38M | +1.28% | Position as of Jun 30, 2026Filing date unknown | |
| 4 | 3.15% | 13.99M | +2.64% | Position as of Jun 30, 2026Filing date unknown | |
| 5 | 2.40% | 10.63M | -0.30% | Position as of Jun 30, 2026Filing date unknown | |
| 6 | 2.35% | 10.40M | -2.83% | Position as of Jun 30, 2026Filing date unknown | |
| 7 | 2.30% | 10.22M | +3.25% | Position as of Jun 30, 2026Filing date unknown | |
| 8 | 1.63% | 7.25M | -3.53% | Position as of Jun 30, 2026Filing date unknown | |
| 9 | 1.46% | 6.47M | +7.47% | Position as of Jun 30, 2026Filing date unknown | |
| 10 | 1.39% | 6.16M | -8.26% | Position as of Jun 30, 2026Filing date unknown |
Recent insider transactions
Costco Wholesale (COST) Form 4 filings
Action codes are translated so open-market buys and sales are separate from awards, gifts, conversions, and tax withholding.
| # | Insider | % company | Action | Shares | Transaction date |
|---|---|---|---|---|---|
| 1 | ADAMO CLAUDINE Officer | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 2.20K | Sep 29, 2026 |
| 2 | FRATES CATON Officer | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 800 | Sep 29, 2026 |
| 3 | ADAMO CLAUDINE Officer | <0.01% | Stock Award(Grant)Transaction code reported in the data source. Check the original Form 4 filing for details.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 4.13K | Sep 10, 2026 |
| 4 | RIEL PIERRE Officer | <0.01% | Stock Award(Grant)Transaction code reported in the data source. Check the original Form 4 filing for details.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 4.55K | Sep 10, 2026 |
| 5 | FRATES CATON Officer | <0.01% | Stock Award(Grant)Transaction code reported in the data source. Check the original Form 4 filing for details.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 4.55K | Sep 10, 2026 |
| 6 | JONES TERESA A Officer | <0.01% | Stock Award(Grant)Transaction code reported in the data source. Check the original Form 4 filing for details.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 4.13K | Sep 10, 2026 |
| 7 | WILCOX WILLIAM RICHARD Officer | <0.01% | Stock Award(Grant)Transaction code reported in the data source. Check the original Form 4 filing for details.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 4.13K | Sep 10, 2026 |
| 8 | KLAUER JAMES C Officer | <0.01% | Stock Award(Grant)Transaction code reported in the data source. Check the original Form 4 filing for details.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 4.13K | Sep 10, 2026 |
| 9 | RUBANENKO YORAM B. Officer | <0.01% | Stock Award(Grant)Transaction code reported in the data source. Check the original Form 4 filing for details.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 4.13K | Sep 10, 2026 |
| 10 | RAIKES JEFFREY S Director | <0.01% | Stock GiftTransaction code reported in the data source. Check the original Form 4 filing for details.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 5.25K | Jul 10, 2026 |
| 11 | DENMAN KENNETH D Director | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 885 | Jun 23, 2026 |
| 12 | FRATES CATON Officer | <0.01% | SaleOpen-market or direct sale reported on Form 4.Transaction context
Position sold = shares sold ÷ (shares sold + holdings after). Separate accounts or security classes may not represent total beneficial ownership. | 700 | Apr 1, 2026 |
Frequently asked
Questions about this quote
Who are the largest COST shareholders?
Blackrock Inc. is the largest reported institutional holder of COST, with 34.20 million shares, or about 7.71% of shares outstanding.
What does the institutional filing activity show for COST?
Costco Wholesale has 10 institutional rows on file: 5 increased or initiated positions and 5 reduced them.
What insider transactions are available for COST?
TECHi shows 84 dated COST insider transactions through Sep 29, 2026, with transaction types kept separate so administrative actions are not presented as open-market trades.
Are COST insiders buying or selling?
The displayed COST activity reads Net selling: 29 sales and 0 purchases. Other transaction types remain separate.
Who is the most active reported COST insider?
VACHRIS ROLAND MICHAEL has the largest absolute share movement in the displayed COST filing rows, totaling 36,581 shares. The action labels provide the transaction context.
All data sources
Search the dated figures used for this view. Each entry identifies its units, reporting period and calculation status.
What this page answers
Check who owns the float and whether insiders are active.
Explore Institutional concentration, insider transaction pattern, and float context.
Keep in mind Filings are delayed or transactions are administrative rather than economic.
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Next open: 2026-10-05 · 9:30 AM America/New_York
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