Shares of warehouse retailer Costco Wholesale (NASDAQ:COST) are just a bit off their 52-week high over the last few days. The pullback occurred after Costco reported second-quarter results, despite 3% comparable-store sales gains over the same period last year. Net income for the quarter came in at $463 million, or $1.05 per share, compared with expectations of $547 million, or $1.08 a share. While the results were unfavorable, they are likely to be short-term, as the company appears to be focusing on keeping prices low and this will likely pay off in the long term.

But what should a Foolish investor be watching for at Costco? Motley Fool analyst Sean O'Reilly says it's the company's long-term competitive advantages, specifically how they relate to comparable-store sales growth. 

So, is now the time for investors to jump into Costco? On today's Stock of the Day, Sean says that the company is fairly valued and expectations for growth are reasonable. Overall, he thinks Costco would make a solid bedrock for any long-term-oriented portfolio.

Mark Reeth has no position in any stocks mentioned. Sean O'Reilly has no position in any stocks mentioned. The Motley Fool recommends and owns shares of Costco Wholesale. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.