Charlie Perkins, a spokesman for New York-based Ernst & Young, declined to comment to Bloomberg on the earnings restatement.

But the auditors are at fault for not identifying problems with the financial controls earlier, Herman Leung, an analyst at Susquehanna Financial Group in San Francisco, told Bloomberg. Leung, who has a neutral rating on the shares, said: "This should have been highlighted by the auditors. The business is growing so fast that it sounds like they don't have the proper financial controls to deal with the growth."

Groupon's struggles with its financial reporting began almost immediately after its June initial public offering. After an SEC review, the company dropped a controversial accounting method just two months after its prospectus, and then restated its 2010 results in September, saying that it had counted the total amount of its daily-deal coupon sales as revenue, including fees paid to merchants.

"This feeds some of the negative sentiment around their disclosure," Ken Sena, an analyst at New York-based Evercore Partners Inc., told Bloomberg News. Evercore has an equal-weight rating on Groupon shares.