CHICAGO ( TheStreet) -- Groupon ( GRPN) shares plunged in extended trading on Friday after revising its reported fourth-quarter and full-year results, its first as a public company. The daily deals site reduced its fourth-quarter revenue by $14.3 million after initially reporting sales of $506.5 million. The revision also resulted in an increase to fourth-quarter operating expenses that reduced the company's operating income by $30 million, net income by $22.6 million and earnings by 4 cents a share.
Groupon blamed the change on a shift in the company's fourth-quarter deal mix and higher price offers, which have higher refund rates. Investors baulked at the revision, pushing Groupon's shares down $1.68, or 9.14%, $16.70 in extended trading. Groupon, however, shrugged off the change. "We remain confident in the fundamentals of our business, as our performance continues to highlight the value that we provide to customers and merchants," explained Jason Child, the Groupon CFO, in a statement released after market close. The Chicago firm, which went public at $20 per share back in early November, also affirmed its first-quarter guidance, reiterating its revenue forecast between $510 million and $550 million and income from operations of $15 million to $35 million. Groupon also said its Form 10-K would include an acknowledgement of "material weaknesses" in its internal controls as per the findings of its independent auditor Ernst & Young LLP. -- Written by James Rogers in New York. >To follow the writer on Twitter, go to http://twitter.com/jamesjrogers. >To submit a news tip, send an email to: firstname.lastname@example.org. Check out our new tech blog, Tech Trends. Follow TheStreet Tech on your wireless devices.