Activist investor Carl Icahn has increased his stake in financially troubled oil and natural gas company Chesapeake Energy (NYSE:CHK) to nearly 9%, according to SEC documents filed today. Since Nov. 12, Icahn has acquired 9.6 million Chesapeake shares under various funds and entities, according to the SEC filing, including 3 million shares just yesterday.

In all, Icahn owns almost 60 million shares, or nearly 9%, of Chesapeake Energy. The aggregate purchase price of the shares was $951 million, according to today's filing. Icahn is famous for being a "corporate raider," taking interests in companies he believes to be poorly managed, and subsequently pushing for shake-ups at the higher levels. He's already been pushing for change at Chesapeake, when his stake earlier this year was at 7.6%.

Chesapeake's stock was trading more than 1% higher around lunchtime on Tuesday. 

John Divine has no positions in the stocks mentioned above. You can follow him on Twitter @divinebizkid and on Motley Fool CAPS @TMFDivine.

The Motley Fool has the following options: long JAN 2013 $16.00 calls on Chesapeake Energy, long JAN 2013 $16.00 calls on Chesapeake Energy, long JAN 2013 $25.00 calls on Chesapeake Energy, long JAN 2014 $20.00 calls on Chesapeake Energy, long JAN 2014 $20.00 calls on Chesapeake Energy, long JAN 2014 $30.00 calls on Chesapeake Energy, long JAN 2014 $30.00 calls on Chesapeake Energy, and short JAN 2014 $15.00 puts on Chesapeake Energy.

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