"The history of Groupon’s chairman, Eric Lefkofsky, was also unearthed, showing a lawsuit-prone entrepreneur who flipped a dot-com company in 1999 only to have it lead to bankruptcy a year later for the firm he had sold it to. And Groupon’s filing shows that when the company privately raised $950 million in a pre-I.P.O. round in January, it paid out $810 million of that to its investors and employees, a red flag for any investor. (Mr. Lefkofsky and his wife took home about $319 million of the total.)"
Source: http://dealbook.nytimes.com/2011/10/17/the-missed-red-flags-...