Jana Took Stake on Groupon Following the Firing of Andrew Mason

Jana Partners LLC, a hedge-fund manager founded by Barry Rosenstein, took a large stake in Groupon Inc.

this quarter, according to a 13F filing with the U.S. Securities and Exchange Commission. With a stake of just over 21.9 million shares -- valued at more than $134 million -- Jana is now the seventh largest shareholder in Groupon, holding about 3.3 percent of the total shares. Traders are already speculating Jana could be taking the position in response to Groupon firing Andrew Mason as the CEO in late February. As an event-driven hedge fund, Jana usually capitalizes on companies undergoing large changes such as mergers, management changes, and bankruptcies, so this trader speculation would make sense. In the wake of Andrew Mason's firing, this deal site has a chance to take a close look at themselves and consider if they are truly providing a customer friendly service. Overall, Jana manages about $4.8 billion in investments and commitments. In addition, the fund acquired about 25 million shares in Zynga

, valued at more than $85 million, and also liquidated a large position in Netflix

.