Groupon Inc. revised its financial results Friday, an unexpected restatement that deepened losses for the daily deals site and once again raised questions about the accounting practices of the newly public company.
As part of the revision, Groupon disclosed a "material weakness" in its internal controls, saying it failed to set aside enough money to cover customer refunds. The accounting issue increased the company's losses in the fourth quarter to $64.9 million, from $42.3 million.
The news sent shares of Groupon tumbling 6 percent in after-hours trading, to $17.29. Shares of Groupon have fallen more than 30 percent since the company went public last fall.
The disclosure highlights current concerns about the reliability of Groupon's financial statements.
Founded only four years ago, the company has experienced astonishing growth as it came to dominate the world of daily coupons. Last year, investors clamored for shares of the newly public company, which was valued as high as $20 billion.
But Groupon has suffered a number of missteps in the harsh glare of scrutiny, particularly related to its accounting.
Last summer, the company was forced to drop a widely criticized profit measure that excluded marketing costs. Several months later, Groupon restated its revenue after the Securities and Exchange Commission challenged its methodology.
On Friday, Groupon said the latest accounting problems related to certain assumptions and forecasts that the company used to calculate its results. In particular, the company said it underestimated customer refunds for higher-priced offers like laser eye surgery.
