What: Shares of online employment and recruitment solutions company Monster Worldwide (NYSE: MWW) fell as much as 15.7% on Thursday. But the loss improved to 9.5% by the time the market closed. The stock's decline followed the company's worse-than-expected revenue, and its underwhelming guidance.

Image source: Monster Worldwide.

So what: Monster reported revenue and non-GAAP EPS of about $158 million and $0.07, respectively. These results compare to revenue and non-GAAP EPS of about $173 million and $0.07 in the year-ago quarter, respectively.

While Monster's EPS was in line with analysts' consensus estimate, revenue was about $2 million lower than expected. But this slight miss may not be the main reason for the sell-off on Thursday: The company's guidance for non-GAAP EPS in the range of breakeven to $0.04 was well below the current consensus analyst estimate for second-quarter non-GAAP EPS of $0.07. This much weaker-than-expected guidance looks like a better contender as the reason for Thursday's sell-off of the stock.

Now what: Going forward, Monster CEO and CFO Tim Yates stated in the company's first-quarter press release that the company will be investing in "a couple of targeted product and marketing areas" aimed at accelerating the company's revenue growth.