Despite the possibility of a default on government debt and a plunge in the stock markets, the Dunkin’ Brands (NASDAQ:DNKN) IPO soared by nearly 47% Wednesday. Basically, investors are desperate to find growth. No doubt, this has been the case with other offerings like Pandora (NYSE:P) and LinkedIn (NYSE:LNKD).

However, there is one upcoming IPO that is looking a bit shaky: Groupon. The company, which is the top provider of online daily deals, has been getting mostly negative buzz. In fact, some bloggers have even called it a Ponzi scheme because of the massive losses.

But now the Securities and Exchange Commission is weighing in. According to a report from CNBC, the agency is concerned about Groupon’s use of a fancy accounting metric called adjusted CSOI (consolidated segment operating income). It conveniently excludes marketing and various noncash costs. All in all, it is a slick way to reduce the impact on the bottom line.  In 2010, adjusted CSOI was $60.6 while the operating loss was a hefty $413 million. Yikes!

The SEC probably will not cancel the offering (this rarely happens). Keep in mind that Groupon has financials that meet Generally Accepted Accounting Principles. Thus, the SEC probably is finding a way to downplay or even the eliminate the use of new metrics in Groupon’s prospectus.

However, this could mean a delay in the IPO — which definitely is a serious thing.  In fact, this might help Groupon’s arch rival, LivingSocial. The company is working hard to file its IPO. So if both companies go public at roughly the same time, it could make it tougher to get momentum.

But there is another important issue for investors: That is, why does Groupon have to resort to accounting games? Does it really have something to hide? Does the company realize it will never be profitable?

Let’s face it. There are thousands of daily-deal sites across the world, which likely puts pressure on margins. Besides, since Groupon is only three years old, it is too early to know the loyalty of its customers. In other words, the company might need to keep ramping up marketing to fuel growth.

Again, the Groupon deal should get done and probably will have a fairly strong debut. But as other strong companies come public — like Zynga and Facebook — it could be tough for the company to sustain a hefty valuation, which currently is pegged above a whopping $20 billion.

Tom Taulli’s latest book is “All About Short Selling” and he has an upcoming book called “All About Commodities.” You can find him at Twitter account @ttaulli.  He does not own a position in any of the stocks named here.