Costco Wholesale Corp. ( COST ) shares are trading lower Thursday after the company released its May sales report.

What To Know: For the four-week period ending June 1, 2025, Costco reported net sales of $20.97 billion, up 6.8% from $19.64 billion a year earlier. For the first 39 weeks of the fiscal year, total net sales reached $201.02 billion, an 8% increase compared to $186.07 billion last year.

Comparable sales rose 4.3% for May across the company. In the U.S., comparable sales were up just 4.1%, while international markets like Canada and other regions rose 3.3% and 6.6%, respectively. E-commerce continued to show stronger growth, up 11.6% for the month.

Stripping out the effects of gasoline prices and foreign exchange, comparable sales were stronger, 6% for the total company, including 5.5% in the U.S. and 12% in e-commerce. However, even those numbers didn't prevent the stock from falling sharply.

One reason for the selloff may be that U.S. same-store sales growth, while positive, lagged behind inflation and didn’t show a major acceleration. Gross margin and membership revenue details weren't included in the May report, leaving gaps in the picture of overall profitability and operational efficiency. Inventory and cost pressures, common issues in the retail sector, may also be on investors’ minds.

Costco's sharp drop in share price suggests the market may have been expecting more aggressive growth, especially given the stock's high valuation. Despite strong year-to-date performance, the nearly 4% decline indicates that investors are looking beyond top-line growth and focusing on margin trends, U.S. consumer demand and the broader retail environment.

COST Price Action: Costco shares were down 4.01% at $1009.47 at the time of writing, according to Benzinga pro.

Read Next:

Trump Announces China Trade Talks, Tesla Stock Slumps: What’s Driving Markets Thursday?

Image Via Shutterstock.