"I think it's largely that the stock was probably pricing in close to a 3-percent comp for Wal-Mart U.S.," he said. "I think that's really the main factor here."
McKeever has a "neutral" rating and a $72 price target on Wal-Mart's shares, and said the stock is "more or less fully valued at its current price."
On Thursday, Wal-Mart also acknowledged that it has expanded its own internal investigation into bribery accusations to the emerging markets Brazil, China, and India.
Despite the announcement, McKeever told CNBC's "Squawk on the Street" that the investigation is not having a big impact on the performance of Wal-Mart stock.
"I mean the stock has performed well in the face of these Mexico bribery allegations and this ongoing investigation," he said. "So I think the investment community has largely discounted that."
Instead, the dive stems from investors' concern about same-store sales figures, he said.
"This is all about sales and whether or not Wal-Mart can comp better than 1.5 to 2 percent, and right now, what we saw this morning seems to suggest that that will be the pattern still going forward," he said.
—By CNBC.com's Katie Little; Follow Her on Twitter @katie_little
Additional News: Retail Sales Fall 0.3%
Additional Views: Is Lousy Wal-Mart Forecast a Broad Sell Signal?______________________________
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Patrick McKeever does not own shares of Wal-Mart or Apple.