A report from CNBC, citing people familiar with the matter, says that the SEC’s review of Groupon has been prolonged by concerns about the company’s accounting metrics, which could keep the much anticipated IPO from happening until late September.

Groupon filed its S-1 documents back in early June, and these were amended earlier this month. The report says:

But the SEC remains focused on at least two of the company’s favored accounting metrics, say the people familiar with the matter: gross profits and consolidated segment operating income, or CSOI.

In June, when Groupon filed for the IPO, it indicated it was aiming to raise $750 million. Last year, of course, the company turned down a reported $6 billion offer from Google, who has since gone on to launch its own Groupon clone called Google Offers.

Groupon CEO Andrew Mason got in a jab at Google Offers at the All Things Digital D9 conference, saying, “What they really did well is integration with Buzz.” Since then, Google has launched the much talked about Google+, which has shown tremendous growth in just a few short weeks. Google has also indicated that it Google Offers will eventually be integrated into Google+.

This week, in fact, they announced an update to the Google Shopper app for iPhone, which includes new Google Offers integration.

Last year, Groupon lost $413 million. Its revenue for Q1 was $644.7 million. The company did acquire Pelago, makers of the Whrrl check-in app, in April.

Morgan Stanley, Goldman Sachs, and Credit Suisse are the IPO’s lead underwriters.