Claudine Adamo, a Costco Wholesale Corp ($COST) executive listed in SEC filings with the title of President, sold 2,200 shares of $COST on September 29, 2026. The open-market sale executed at $915.93 per share for a total of $2,015,046. The Form 4 covering the transaction was filed with the SEC on September 30, one day after the trade date, and showed 7,133.51 shares owned after the sale.
The September 29 sale followed two earlier open-market sales reported by Adamo. On March 9, 2026, she sold 730 shares at $1,003.02 per share, totaling $732,205.33, in a filing made on March 11, two days after the trade. On October 24, 2025, she sold 2,700 shares at $935.68 per share, totaling $2,526,336, in a filing made the same day. Across the three reported sales, she sold 5,630 shares for a combined $5,273,587.33.
Adamo was not the only $COST insider to report a sale on September 29. Caton Frates, also listed with the President title, sold 800.638 shares at the same $915.93 per-share price, totaling $733,328.36, in an open-market transaction filed on September 30. Frates had previously reported an open-market sale of 700 shares at $993.00 per share on April 1, 2026, and a sale of 1,540 shares at $910.02 per share on September 29, 2025. Across his three reported sales, Frates sold 3,040.638 shares for a combined $2,829,859.16. The two September 29, 2026 sales by Adamo and Frates totaled $2,748,374.36 at the $915.93 price, and were the only $COST insider transactions reported in September 2026.
Separately, recent congressional STOCK Act disclosures on $COST included purchases and sales by House and Senate members. Representative Dan Newhouse reported a purchase on July 10, 2026, disclosed on July 17. Representative Richard Dean Dr Mccormick reported a sale on July 30, 2026, disclosed on August 14. Representative Ro Khanna reported $COST purchases on February 24, 2026, and January 6, 2026, among other filings. Representative Gilbert Cisneros reported a purchase on January 30, 2026, and a sale on December 24, 2025. Senator Markwayne Mullin reported a purchase on December 29, 2025, with a disclosed midpoint amount of about $15,001. The disclosures came from members of both parties. Congressional dollar figures are midpoint estimates of the bracketed ranges disclosed under the STOCK Act; the midpoint for most of the recent $COST disclosures was about $1,001.
On the trade date, $COST shares closed at $924.59, after trading between $912.66 and $925.97. The $915.93 per-share execution price compared with $1,003.02 reported for Adamo's March 2026 sale and $993.00 reported for Frates' April 1, 2026 sale. Costco, a wholesale retailer with a market capitalization near $401 billion, saw both September 29 sales reported to the SEC one day after the trade date.