2. Groupon

What It Does:Provide discounted gift certificates and daily deals.
IPO Date: November 4, 2011
Money raised: $700 million.

Groupon may be the most controversial company to go public. Here's why: No one believes Groupon is worth much of anything at all. Google attempted to buy the Chicago-based company back in 2010 for $6 billion, but Groupon turned down the offer. The same year the company raised $950 million in venture capital funding which gave it a valuation of $6.4 billion. However, it later came out that the company used most of the money raised to pay its three founders and a few early investors. It was also revealed that it loses around $100 million every quarter. Despite push back from analysts who said its financials were murky and inaccurate, Groupon still forged ahead with its IPO and raised an astounding $700 million, giving it a 12.7 billion valuation. Unfortunately, a month later, Groupon's stock price dropped by a half.