SEC Form 4
Costco Wholesale Corp (COST) insider trading
In the 12 months to Oct 24, 2026, 10 COST insiders reported open-market sales of $18.3M across 14 filings; no open-market purchases were filed.
Latest filing · Last 12 months · Source: SEC EDGAR · How we count
- Open-market sales
- $18.3M
- 14 filings · 10 insiders
- Open-market purchases
- $0
- 0 filings
Who traded COST, and when
- Sale
COST daily close from Oct 24, 2025 to Oct 23, 2026, between $850.00 and $1,094.32, last $1,003.32. 14 sale and 0 purchase filings by 10 insiders, marked at their filing dates. Claudine Adamo, Executive Vice President: sold $5.3M across 3 filings, first filed Oct 24, 2025, last Sep 30, 2026. William Richard Wilcox, Executive Vice President: sold $3.3M across 2 filings, first filed Nov 12, 2025, last Oct 14, 2026. Javier Polit, Executive Vice President: sold $2.3M across 1 filing, first filed Dec 31, 2025, last Dec 31, 2025. Caton Frates, Executive Vice President → Sr. Executive Vice President: sold $1.4M across 2 filings, first filed Apr 1, 2026, last Sep 30, 2026. James C. Klauer, Executive Vice President: sold $1.4M across 1 filing, first filed Jan 15, 2026, last Jan 15, 2026. Russell D. Miller, Sr. Executive Vice President: sold $1.4M across 1 filing, first filed Jan 12, 2026, last Jan 12, 2026. 4 others: sold $3.3M across 4 filings, first filed Oct 24, 2025, last Jun 25, 2026.
Largest mark · tap a row for others
Claudine Adamo · Executive Vice President
Sale $2,526,336
2,700 shares at $935.68 avg
Filed Oct 24, 2025
Close on filing date $932.14
Claudine Adamo · Executive Vice President
Executive Vice President
$5.3M soldWilliam Richard Wilcox · Executive Vice President
Executive Vice President
$3.3M soldJavier Polit · Executive Vice President
Executive Vice President
$2.3M soldCaton Frates · Executive Vice President → Sr. Executive Vice President
Executive Vice President → Sr. Executive Vice President
$1.4M soldJames C. Klauer · Executive Vice President
Executive Vice President
$1.4M soldRussell D. Miller · Sr. Executive Vice President
Sr. Executive Vice President
$1.4M sold4 others
Combined, one mark per week
$3.3M soldHas Costco Wholesale Corp's CEO sold stock?
No. Roland Michael Vachris (CEO) made no open-market sales filed as CEO in the last 12 months.
Open-market trades
14 filings in the last 12 months| Insider | Role | Sold | Bought | Filings | Pre-arranged (10b5-1) | Last filed |
|---|---|---|---|---|---|---|
| Claudine Adamo | Executive Vice President | $5.3M | — | 3 | — | |
| William Richard Wilcox | Executive Vice President | $3.3M | — | 2 | — | |
| Javier Polit | Executive Vice President | $2.3M | — | 1 | — | |
| Caton Frates | Executive Vice President → Sr. Executive Vice President | $1.4M | — | 2 | — | |
| James C. Klauer | Executive Vice President | $1.4M | — | 1 | — | |
| Russell D. Miller | Sr. Executive Vice President | $1.4M | — | 1 | — | |
| Tiffany Marie Barbre | Other | $1.2M | — | 1 | — | |
| Kenneth D. Denman | Director | $847.3K | — | 1 | — | |
| Teresa A. Jones | Executive Vice President | $838.3K | — | 1 | — | |
| Susan L. Decker | Director | $437.4K | — | 1 | — |
| Filed | Insider | Type | Shares | Avg price | Value | Held after | Source |
|---|---|---|---|---|---|---|---|
traded | William Richard Wilcox Executive Vice President | Sale | 1,100 | $958.21 | $1.1M | 3,094 | |
traded | Claudine Adamo Executive Vice President | Sale | 2,200 | $915.93 | $2.0M | 7,134 | |
traded | Caton Frates Sr. Executive Vice President | Sale | 801 | $915.93 | $733.3K | 7,912 | |
traded | Kenneth D. Denman Director | Sale | 885 | $957.45 | $847.3K | 4,779 | |
traded | Caton Frates Executive Vice President | Sale | 700 | $993.00 | $695.1K | 5,815 | |
traded | Claudine Adamo Executive Vice President | Sale | 730 | $1,003.02 | $732.2K | 6,121 | |
traded | Teresa A. Jones Executive Vice President | Sale | 850 | $986.26 | $838.3K | 4,228 | |
traded | Susan L. Decker Director | Sale | 458 | $955.00 | $437.4K | 8,532 | |
traded | James C. Klauer Executive Vice President | Sale | 1,500 | $939.00 | $1.4M | 44,837 | |
traded | Russell D. Miller Sr. Executive Vice President | Sale | 1,500 | $916.32 | $1.4M | 8,240 | |
traded | Javier Polit Executive Vice President | Sale | 2,607 | $866.28 | $2.3M | 10,190 | |
traded | William Richard Wilcox Executive Vice President | Sale | 2,400 | $930.13 | $2.2M | 2,000 | |
traded | Claudine Adamo Executive Vice President | Sale | 2,700 | $935.68 | $2.5M | 6,851 | |
traded | Tiffany Marie Barbre Other | Sale | 1,239 | $934.62 | $1.2M | 5,155 |
GET /stocks/filings/vX/form-4?tickers=COST&filing_date.gte=2025-10-24&sort=filing_date.desc&limit=500{
"status": "OK",
"results": [
{
"tickers": [
"COST"
],
"issuer_cik": "0000909832",
"owner_cik": "0002087546",
"accession_number": "0000909832-26-000098",
"form_type": "4",
"filing_date": "2026-10-14",
"period_of_report": "2026-10-13",
"issuer_name": "COSTCO WHOLESALE CORP /NEW",
"issuer_trading_symbol": "COST",
"owner_name": "Wilcox William Richard",
"is_officer": true,
"officer_title": "Executive Vice President",
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common Stock",
"transaction_timeliness": "O",
"aff_10b5_one": false,
"transaction_date": "2026-10-13",
"transaction_code": "S",
"equity_swap_involved": false,
"transaction_shares": 1100,
"transaction_price_per_share": 958.205,
"transaction_acquired_disposed": "D",
"shares_owned_following_transaction": 3094.391,
"transaction_value": 1054025.5,
"direct_or_indirect": "D"
},
{
"tickers": [
"COST"
],
"issuer_cik": "0000909832",
"owner_cik": "0001916124",
"accession_number": "0000909832-26-000088",
"form_type": "4",
"filing_date": "2026-09-30",
"period_of_report": "2026-09-29",
"issuer_name": "COSTCO WHOLESALE CORP /NEW",
"issuer_trading_symbol": "COST",
"owner_name": "Adamo Claudine",
"is_officer": true,
"officer_title": "Executive Vice President",
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common Stock",
"transaction_timeliness": "O",
"aff_10b5_one": false,
"transaction_date": "2026-09-29",
"transaction_code": "S",
"equity_swap_involved": false,
"transaction_shares": 2200,
"transaction_price_per_share": 915.93,
"transaction_acquired_disposed": "D",
"shares_owned_following_transaction": 7133.51,
"transaction_value": 2015046,
"direct_or_indirect": "D"
}
]
}
// trimmed to 2 resultsThe response includes every Form 4 record; this page keeps open-market purchases and sales on common stock and removes duplicate joint-filer rows.
Other insider activity (not market trades) · 73 records
- Tax withholding45 records
- Grants and awards21 records
- Gifts6 records
- Other1 record
Reported on Form 4 but not purchases or sales in the market, so not counted in the totals above.
Build this yourself
This page joins two Massive endpoints: Form 4 filings and daily prices. Ask an agent to watch for new filings:
Using the Massive API (massive.com/docs/llms.txt), check Form 4 filings for COST every day with transaction_code=P and tell me when an insider files an open-market purchase, with their role, shares, price and the filing link.
How to read this page
- Open-market purchase or sale
- A buy or sell of the company's stock at market price. Grants, option exercises, shares withheld for tax, gifts and employee stock plan purchases are listed separately and not counted.
- Role
- The title on each filing. Someone whose title changed shows more than one.
- Filing date
- Insiders have two business days to report a trade. Totals and the chart use the filing date, when the trade became public.