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What: Shares of outsourcing services provider ExlService Holdings (Nasdaq: EXLS) were soaring today, gaining as much as 18% in intraday trading after announcing first-quarter results.

So what: There's no guesswork needed to figure out why ExlService's stock is firing on all cylinders today. For the first quarter, the company reported $0.33 in adjusted earnings per share, which was up 38% from a year ago and easily topped the $0.25 that Wall Street expected. The top line was similarly positive, as revenue gained 34% from last year and also topped analysts' estimates.

Now what: While strong results from the quarter can get investors excited, hints about a better future can make them go bananas. In ExlService's earnings press release, management boosted its outlook for all of 2011. Thanks in part to the just-announced acquisition of Outsource Partners International, ExlService increased its 2011 revenue guidance from a range of $295 million to $305 million to a range of $347 million to $355 million. The company is keeping its operating margin guidance fixed, so the higher revenue should translate into higher profit as well.

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Fool contributor Matt Koppenheffer does not have a financial interest in any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.