According to a report in the Wall Street Journal, the company behind one of the most highly anticipated initial public offerings in recent memory - Chicago-based group-buying pioneer Groupon - is reconsidering its decision to go public due to the recent volatility in the stock market. While the IPO hasn’t been cancelled, a source told the WSJ that it has been postponed indefinitely, and the pre-IPO roadshow has ben cancelled. But was it market volatility that pulled the rug out from under Groupon’s public debut, or the repeated missteps by the company and its CEO, combined with growing skepticism about the viability of its business model? The Groupon IPO has been facing a number of significant headwinds, and these have a lot more to do with the Chicago startup’s business than with economic conditions. One of them is a Securities and Exchange Commission inquiry into the circumstances surrounding a leaked memo by Co-Founder and CEO Andrew Mason that made its way online recently. According to the WSJ, the regulator has been asking questions about the leak, since discussing the financial status of the company is a breach of what has come to be known as the pre-IPO “quiet period.” That’s the second time the SEC has shown a more than passing interest in Groupon. After the company filed its S-1, the regulator also had discussions with the startup about its use of a controversial - and non-standard - financial metric called “adjusted consolidated segment operating income.” Although Groupon argued that this was justified by the way its business operates, using this metric made the company’s financial results look significantly better than they would have otherwise: instead of a $450-million loss in 2010, for example, Groupon showed an $60-million operating profit. Get the full story at GigaOM