In the following video, Fool analysts Isaac Pino and Blake Bos look at some of the biggest risks facing Costco Wholesale (COST 0.17%).

One of Costco's biggest opportunities is international expansion, but it's also one of its biggest risks, Blake says. Plenty of retailers have stumbled when expanding outside the U.S., including Home Depot (HD -1.77%), which had to pull back from its expansion into China, Isaac adds.

Costco could face similar problems entering into markets where the culture is very different. Membership renewal rates have been slightly lower internationally, so it's something investors must watch.

Valuation is another risk. Costco sells at a premium, and retailers hit hurdles along the way. If it were to miss on earnings, it could take a hit, Isaac says.

Domestically, Costco is running out of opportunities to grow, Isaac says. At this valuation, he adds, that makes a runway for international growth even more important to Costco and its investors.