Costco Wholesale (COST) insider buying and selling
Every Table I transaction reported by directors and officers of S&P 500 companies on SEC Form 4 filings (2 business days to file): each row labeled with its official transaction code, nothing filtered out beforehand.
Open-market purchases (code P) are the rare signal, in green; sales (code S) are common and often pre-scheduled (10b5-1). Table II (derivatives) is not included: its prices are exercise prices, not market values. Guide: insider buying.
| Date | Ticker | Insider | Role | Shares | Price | Amount | % of stake | Type / filing |
|---|
Download these transactions as CSV No account, no sign-up. The data is public: it comes from SEC Form 4 filings.
Costco Wholesale Corporation (COST) insider buying and selling: no purchases, 17 sales
82 Form 4 Table I transactions filed with the SEC by Costco Wholesale Corporation insiders between 2025-09-04 and 2026-10-14 (15-month history): 0 open-market purchases and 17 sales, plus 65 transactions under other Form 4 codes, broken down one by one below. The largest open-market trade is a sale of $3.1M by Miller Russell D on 2025-09-29.
Costco Wholesale insider buying and selling over the last 12 months
Between Oct 21, 2025 and Oct 20, 2026, Costco Wholesale insiders filed 15 sales worth $18.3M on the open market, and no purchases.
The biggest seller was Adamo Claudine (Executive Vice President): $5.3M in 3 sales, out of 10 different sellers.
The largest trade of the period was a sale of $2.5M on Oct 24, 2025, by Adamo Claudine (Executive Vice President). Form 4 on sec.gov (0000909832-25-000126).
None of the 15 sales carries the 10b5-1 plan flag on the Form 4 (sales scheduled months ahead).
The last three months show 3 sales, against 1 in the three before. The latest sale from Oct 13, 2026.
Against its sector (Consumer Defensive, 33 companies with an insider page on this site), over the same dates the median is 5 sales and 1 purchase on the open market. Costco Wholesale has more sales than 27 of the other 32, ranks 12 of 33 by net dollars sold, and 17 of the 33 have at least one purchase.
The 20 most important trades
With no open-market purchases, the table starts with COST's sales, largest first. The full history is in the tool above, already searched.
See all 82 COST trades in the full history →
| Trade date | Filed | Insider | Role | Amount | Code | Filing |
|---|---|---|---|---|---|---|
| 2025-09-29 | 2025-10-01 | Miller Russell D | Sr. Executive Vice President | $3.1M | S — Open-market sale Indirect holding, through: Miller Family Trust Form 4 footnoteF1 Represents one (1) share transferred from direct to indirect holdings inadvertently omitted from the Form 4 filed on September 24, 2025. | SEC |
| 2025-10-24 | 2025-10-24 | Adamo Claudine | Executive Vice President | $2.5M | S — Open-market sale | SEC |
| 2025-11-07 | 2025-11-12 | Wilcox William Richard | Executive Vice President | $2.2M | S — Open-market saleForm 4 footnoteF1 On October 23, 2025, the reporting person received a distribution of 4,400.9692 shares of common stock previously beneficially owned through Costco's 401(k) plan. Upon the distribution, a fractional share of .9692 was liquidated and the total amount owned was reduced by such amount. | SEC |
| 2026-09-29 | 2026-09-30 | Adamo Claudine | Executive Vice President | $2.0M | S — Open-market sale | SEC |
| 2025-12-29 | 2025-12-31 | Polit Javier | Executive Vice President | $1.8M | S — Open-market saleForm 4 footnoteF1 The price shown is a weighted average price for shares sold in multiple transactions; the sale prices ranged from $867.16 to $867.325 per share. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. | SEC |
| 2026-01-14 | 2026-01-15 | Klauer James C | Executive Vice President | $1.4M | S — Open-market sale | SEC |
| 2025-09-29 | 2025-09-30 | Frates Caton | Executive Vice President | $1.4M | S — Open-market sale | SEC |
| 2026-01-09 | 2026-01-12 | Miller Russell D | Sr. Executive Vice President | $1.4M | S — Open-market sale Indirect holding, through: Miller Family Trust | SEC |
| 2025-10-24 | 2025-10-24 | Barbre Tiffany Marie | Officer | $1.2M | S — Open-market saleForm 4 footnoteF4 The price shown is a weighted average price for shares sold in multiple transactions; the sale prices ranged from $934.47 to $934.84 per share. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. | SEC |
| 2026-10-13 | 2026-10-14 | Wilcox William Richard | Executive Vice President | $1.1M | S — Open-market sale | SEC |
| 2026-06-23 | 2026-06-25 | Denman Kenneth D | Director | $847k | S — Open-market saleForm 4 footnoteF1 The price shown is a weighted average price for shares sold in multiple transactions; the sale prices ranged from $957.44 to $957.63 per share. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. | SEC |
| 2026-01-21 | 2026-01-23 | Jones Teresa A. | Executive Vice President | $838k | S — Open-market saleForm 4 footnoteF1 The price shown is a weighted average price for shares sold in multiple transactions; the sale prices ranged from $986.220 to $986.480 per share. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. | SEC |
| 2026-09-29 | 2026-09-30 | Frates Caton | Sr. Executive Vice President | $733k | S — Open-market sale | SEC |
| 2026-03-09 | 2026-03-11 | Adamo Claudine | Executive Vice President | $732k | S — Open-market sale | SEC |
| 2026-04-01 | 2026-04-01 | Frates Caton | Executive Vice President | $695k | S — Open-market sale | SEC |
| 2025-12-30 | 2025-12-31 | Polit Javier | Executive Vice President | $482k | S — Open-market sale | SEC |
| 2026-01-16 | 2026-01-20 | Decker Susan L | Director | $437k | S — Open-market sale | SEC |
| 2025-10-22 | 2025-10-24 | Frates Caton | Executive Vice President | $2.6M | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF1 This transaction is a withholding by the Company for taxes in connection with the vesting of previously granted restricted stock units. The price represents the closing market price of Costco common stock on Nasdaq on October 22, 2025. | SEC |
| 2025-10-22 | 2025-10-24 | Vachris Roland Michael | President and CEO | $2.5M | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF3 This transaction is a withholding by the Company for taxes in connection with the vesting of previously granted restricted stock units. The price represents the closing market price of Costco common stock on Nasdaq on October 22, 2025. | SEC |
| 2025-10-22 | 2025-10-24 | Sullivan John Christopher | Executive VP | $2.4M | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF3 This transaction is a withholding by the Company for taxes in connection with the vesting of previously granted restricted stock units. The price represents the closing market price of Costco common stock on Nasdaq on October 22, 2025. | SEC |
The period balance: money in, money out
In the Form 4 filings submitted between Sep 4, 2025 and Oct 14, 2026 there is not one open-market purchase of Costco Wholesale Corporation: 17 sales worth $22.8M and zero dollars bought.
Only codes P and S count, where an insider puts in or takes out their own money. A selling balance like Costco Wholesale Corporation's is the norm in the S&P 500, where much of the pay comes as stock. It is not a recommendation to buy or sell: it is what was filed.
Every transaction, code by code
| Code | What it means | Trades | Reported amount |
|---|---|---|---|
| A | Grant or award | 29 | $0 |
| F | Tax withholding (shares surrendered for taxes) | 25 | $32.8M |
| S | Open-market sale | 17 | $22.8M |
| G | Gift | 10 | $0 |
| I | Discretionary transaction in a plan | 1 | $636k |
| Total | Everything filed in the period | 82 | $56.3M |
39 of the 82 rows carry no usable amount on the Form 4: they count as trades and add $0. The code labels come from the SEC index.
Who has traded
Over the 15 months of history, 24 distinct people or entities have filed Costco Wholesale Corporation transactions: none bought on the open market and 10 sold. Counted by CIK, the fixed number the SEC gives each filer, and not by name, which each filer types their own way.
Of the 10 who sold on the open market (17 sales in all), the three biggest sellers account for $13.0M of the $22.8M: 57% of the money in three people.
| Filer | Role | Transactions | Bought (count) | Sold (count) | Last filed |
|---|---|---|---|---|---|
| Adamo Claudine | Executive Vice President | 8 | — | $5.3M (3) | 2026-09-30 |
| Miller Russell D | Sr. Executive Vice President | 6 | — | $4.5M (2) | 2026-01-12 |
| Wilcox William Richard | Executive Vice President | 4 | — | $3.3M (2) | 2026-10-14 |
| Frates Caton | Sr. Executive Vice President | 8 | — | $2.8M (3) | 2026-09-30 |
| Polit Javier | Executive Vice President | 4 | — | $2.3M (2) | 2025-12-31 |
| Klauer James C | Executive Vice President | 6 | — | $1.4M (1) | 2026-09-14 |
| Barbre Tiffany Marie | Officer | 3 | — | $1.2M (1) | 2025-10-24 |
| Denman Kenneth D | Director | 3 | — | $847k (1) | 2026-06-25 |
Shown here are the 8 who moved the most money, out of 24. The rest are in the full history, one link above. The name links to all their trades, in any company. "Transactions" counts any code; the money, open market only. Role: from their latest filing.
Month by month
By the month the trade was executed, not the month it was filed; months with no trades show zero. The busiest month was Jan 2026: 0 purchases and 4 sales, worth $4.1M. 5 of the 15 months have none.
| Month | Purchases | Amount | Sales | Amount |
|---|---|---|---|---|
| Aug 2025 | 0 | $0 | 0 | $0 |
| Sep 2025 | 0 | $0 | 2 | $4.5M |
| Oct 2025 | 0 | $0 | 2 | $3.7M |
| Nov 2025 | 0 | $0 | 1 | $2.2M |
| Dec 2025 | 0 | $0 | 2 | $2.3M |
| Jan 2026 | 0 | $0 | 4 | $4.1M |
| Feb 2026 | 0 | $0 | 0 | $0 |
| Mar 2026 | 0 | $0 | 1 | $732k |
| Apr 2026 | 0 | $0 | 1 | $695k |
| May 2026 | 0 | $0 | 0 | $0 |
| Jun 2026 | 0 | $0 | 1 | $847k |
| Jul 2026 | 0 | $0 | 0 | $0 |
| Aug 2026 | 0 | $0 | 0 | $0 |
| Sep 2026 | 0 | $0 | 2 | $2.7M |
| Oct 2026 | 0 | $0 | 1 | $1.1M |
The last month may be partial: a Form 4 is filed up to two business days later. The table does not say whether the pattern is good or bad; it says when it happened.
Costco Wholesale Corporation (COST) analysis page →
Other Consumer Defensive companies with insider trades
All 500 are listed in the section index →
Which insiders are buying their own company stock →
How to read this data
None of the 17 sales in the table is flagged as scheduled (10b5-1 plan), the kind signed months ahead and executed automatically. Costco Wholesale has no open-market purchase (code P) in the history, the most common case in the S&P 500: insiders are already paid in stock. The latest filing is from Oct 14, 2026, and a Form 4 arrives up to two business days after the trade.
9 of the 20 rows in the table carry footnotes from the Form 4 itself, folded into the code column and copied verbatim; a row with no footnote means the filing has none.
Guide: Insider buying · all guides
What is behind these trades
The concepts on this page, explained from scratch in the Academy. Free, no account.
- What the efficiency hypothesis says and what it does NOT sayIf an insider's purchase is public and anyone can read it, is there any information left in it? That is the exact question that brings people here.
- Who really moves the market: the types of investorWho sits on the other side of each order, and where a company's own insiders fit among them.
- Supply, demand and price: why it rises and falls constantlyHow a piece of news ends up inside the price, and why the reaction to a filed sale is rarely the one you would expect.
Source: SEC EDGAR Form 4. This is a list of public facts, not financial advice or a recommendation to buy or sell.