A trio of prominent hedge funds have powered up in recent days. New York activist hedge fund shop Jana Partners and Carl Icahn's Icahn Investment Management added stakes in Andarko Petroleum Corp. in the fourth quarter. 

Icahn now owns 3.2% of The Woodlands, Texas-based Andarko, while Jana holds 0.9% stake in the company.

Jana, which paid $283.2 million for its Andarko shares, also bought 0.7% of Hess Corp. for $236 million, it said in a Securities and Exchange Commission filing.

Meanwhile, San Francisco-based Farallon Capital Management is partnering with Indian billionaire Lakshmi Mittal to buy a big chunk of a power unit of Indiabulls Real Estate.

Farallon is buying 23.4%, and Mittal 14.1%, of Sophia Power Co. Indiabulls will then merge Sophia and its Indiabulls Power Services; Farallon will own 17.9% of the merged company and Mittal 10.7%.