Warehouse retailer Costco (COST -1.31%) is going through the fourth quarter of fiscal year 2025. The financial report will probably show up in the last week of September -- and you might want to pick up a few Costco shares before then.
You see, Costco's sales are rising despite a choppy economy -- and the growth drivers might surprise you.
Monthly sales show Costco's momentum building
In a rare display of voluntary transparency, Costco reports basic sales results every month. May results showed a 6.8% year-over-year sales increase to $21 billion. That's a robust result, compared to Costco's 5.7% revenue gains in the third quarter, and even better in the context of 2.9% sales growth for arch rival Walmart in the same period.
Last week, Costco reported June sales of $26.4 billion. That's an 8% jump from June 2024, accelerating Costco's already healthy revenue growth.
Broad success in a tight economy
The fun doesn't stop there. As expected, e-commerce was Costco's fastest-growing segment in June. But it wasn't the most significant provider of business acceleration, as the rate of online-sales growth actually slowed down a tiny bit from May to June.
At the same time, revenue gains accelerated modestly in the U.S. and faster in Canada. None of these rising metrics could compete with Costco's other international sales, which jumped 10.9% year over year. That's a staggering improvement from 6.6% in May.
Costco enjoys robust growth across all segments, despite weak consumer confidence. This is the incredible reason why Costco looks like a buy today.

Image source: Getty Images.
Premium prices for a premium retailer
Costco's stock isn't cheap. Shares are trading at the lofty valuation of 55.6 times earnings and 59.5 times free cash flow. These are some of the highest multiples in the entire sector of consumer staples stocks.
However, you get what you pay for. Costco is an expertly managed retailer that keeps surprising investors. Don't back up the proverbial truck, but I recommend grabbing some Costco stock before September's full Q4 2025 report. The sales updates point in a shareholder-friendly direction.