Costco Insiders "Sold" $24.5 Million. About $10 Million of It Was Tax Withholding.
Costco's insider screen shows $24.5 million of net selling right after a record 10-K. NexusAlert's Company Dossier shows how much was tax withholding and how much was real sales.
Claudine Adamo sold 2,200 Costco shares on September 29. Costco’s insider screen says executives sold $24.5 million.
Costco’s Company Dossier shows $24.5 million of net insider selling across 34 Form 4 transactions, in the same week its 10-K confirmed fiscal 2026 net income of $9.226 billion, up 14%. The filing is the annual report for the year ended August 30, and NexusAlert flagged it as a High severity opportunity alert when it posted.
Adamo, an executive vice president, sold 2,200 shares at $915.93, about $2.0 million, according to her Form 4. The form does not mark the sale as made under a 10b5-1 plan, and she still holds about 7,100 shares directly. Put that next to a $24.5 million headline figure and the question writes itself: are Costco’s executives heading for the exits?
The honest answer takes one more click than the headline does.
What the 10-K says
Net income was $9,226 million, up 14% from $8,099 million. Diluted EPS rose to $20.76 from $18.21. Net sales reached $297.2 billion, up 10%, and membership fees added $5.9 billion. Costco opened 28 warehouses, 25 net of relocations, and raised its quarterly dividend 13%.
Most coverage came from the September 25 earnings release. The 10-K adds the language around it. It names Walmart, Target, Kroger and Amazon as significant competitors and says Costco intends to keep opening warehouses in new markets, which is where the “competitive moat” and “new market entry” flags on the alert come from.
Take the $24.5 million apart
Open the Insider activity card and the by role bar says officers account for $23.2 million. That sounds like executives selling. The expanded Form 4 table says otherwise.
About $10.2 million of the total is tax withholding, shares Costco holds back to cover taxes when restricted stock vests. Seven executive vice presidents had $9.1 million withheld on a single day, September 13, the same day eight restricted stock unit vests posted at $0. Nobody chose to sell those shares.
What is left is about $13.6 million of open market sales, 12 of them, by nine insiders over the past year. Two of the nine are directors. The largest single transaction was $2.2 million, by executive vice president William Richard Wilcox last November. The rest of the gap is roughly $0.6 million in other dispositions.
The score that cuts the other way
None of this makes the insider picture clean. Costco’s Insider Conviction score is 1.1 out of 10, in the bottom 11% of companies NexusAlert scores. None of the 34 Form 4 line items is an open market purchase, and the Dossier lists 14 Form 144 notices of planned selling worth $15.5 million this period, $2.7 million of it in the trailing 90 days. A weak score describes a year of sales with no buying to offset them.
It does not describe the business. The same page scores Earnings Quality at 9.5 and Financial Strength at 9.7, top 5% and top 3% of companies scored. The overall score is 20.3 out of 30, with three of five pillars rated. Two true things about one company, and neither cancels the other. This is not investment advice.
The lesson
A net selling number is a receipt, not a confession. It adds up everything that left an insider’s account, whether they chose it or a vesting schedule did. The line items tell you who, why and how much, and they take about a minute to read.
Read the whole filing, not the headline.
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Sources
- Costco Wholesale Corp, Form 10-K for the fiscal year ended August 30, 2026, SEC EDGAR
- Costco Wholesale Corporation Reports Fourth Quarter and Fiscal Year 2026 Operating Results, Costco Investor Relations
- Costco Reports $93.9 Billion In Q4 Sales And $297.2 Billion In Fiscal 2026 Sales, Pulse 2.0
- Costco fourth quarter and fiscal 2026 results, Finviz
- Form 4 filed by Claudine Adamo, Costco Wholesale Corp, September 29, 2026 transaction, SEC EDGAR
- Costco insider transactions, Quantisnow
- SEC EDGAR, Costco Wholesale Corp (CIK 0000909832), Forms 4 filed over the trailing twelve months
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