What: Shares of data center company 21Vianet Group (NASDAQ:VNET) fell as much as 14.3% following its second-quarter earnings report, which was released on Tuesday after market close. At the time of this writing, the stock is down about 12.6% during the trading day.

The stock's sell-off on Wednesday was likely driven by the company's worse-than-expected adjusted loss per share.

Image source: 21Vianet.

So what: 21Vianet reported revenue of 910.8 million RMB, or $137.2 million, rising 5.1% from the year-ago quarter. The company's adjusted loss per share was $0.17.

These results were mixed compared to analysts' expectations. On average, analysts were expecting 21Vianet to report revenue and EPS of $128.2 million and a loss of $0.09 per share, respectively.

21Vianet Group CEO Steve Zhang admitted in the company's second-quarter press release that 21Vianet experienced "headwinds in certain markets," but said the company is "pleased to report that core business areas, including IDC, Cloud and VPN gained solid growth momentum in the second quarter." 21Vianet's worse-than-expected loss is likely related to the company's pricing pressure in its managed network services, which CFO Terry Wang said "continued to limit our top line growth" in the segment.

Now what: Going forward, Wang asserts the company is making progress on its cost-control efforts -- a feat he believes will play a role in helping "reignite margin growth going forward," he said.

"[W]e are pleased with our operations team's progress on cost control front," Wang said, "which is yet to be fully reflected in our quarterly financial results and should yield positive results in the coming quarters."

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.