Groupon’s stock fell 14% today, and Businessweek is reporting concerns that the company’s growth is slowing down. The Businessweek article outlines numerous worries and weaknesses in the Groupon business model, and the scrutiny it received from Securities and Exchange Commission for the way it accounted for revenue in an early filing.

In a note to investors, Collins Stewart analyst Mayuresh Masurekar said that he believes Groupon’s growth from signing up more subscribers and adding to its list of merchants is slowing.

The dailyfinance also reports numerous concerns about the Groupon business model, under the sub-headline: The Business Model Smells Funny. In fact it goes as far as to tell readers not to buy the Groupon stock.

Here’s how the dailyfinance article wraps up:

This is a harder model to pull off than it seems on paper and it may not be long before only merchants who need to deeply discount their food and spa services to attract customers will be participating. A year ago, Groupon shut down the social component where users could comment on deals. It was a great way to expose iffy merchants or question the advertised savings. Now Groupon limits the communication to questions that get answered.

What’s Groupon hiding? You probably don’t want to stick around to find out.

Source: businessweek, dailyfinance.