Chesapeake, based in Oklahoma City, has tumbled 37 percent this year, the worst performance by an oil and gas producer in the Standard & Poor's 500 Index. The shares, which fell 24 percent in the six weeks Pickens's fund was selling the bulk of its stake, declined 4.2 percent to $14.04 in New York yesterday, the lowest closing price since March 2009.

Chesapeake's board announced May 1 it will strip McClendon, who co-founded the company 23 years ago, of his chairmanship. The IRS, SEC and board are reviewing personal loans McClendon obtained using his stakes in company-operated wells, some of which involved borrowing from financiers that also did business with Chesapeake.

McClendon, 52, will remain CEO as the company seeks to sell $20.5 billion in assets this year and next to plug a cash-flow shortfall. Philip Weiss, a New York-based analyst for Argus Research, has estimated the funding gap may reach $16 billion by the end of 2013.

Bridge Loan

Chesapeake has borrowed $4 billion at 8.5 percent interest from Goldman Sachs Group Inc. and Jefferies Group Inc. to tide it over until the company can raise cash by selling oilfields in Texas and a stake in some Oklahoma and Kansas prospects.

Chesapeake's largest investor, Southeastern Asset Management, on May 7 said management should consider selling the company if the price is right. It urged Chesapeake to focus on operations rather than engaging in public relations and appearing at conferences with Wall Street analysts.

Jay Rosser, a spokesman for Pickens, didn't respond to phone message yesterday seeking an interview with his boss. Jim Gipson, a Chesapeake spokesman, declined to make McClendon available for an interview.

"Aubrey's a visionary," Pickens said yesterday. "He gets out over his skis sometimes, but don't bet against Aubrey."

McClendon and Pickens have more often seen eye-to-eye on business. In July, Chesapeake agreed to invest $150 million in Clean Energy Fuels Corp., a California-based company that builds stations for natural-gas fueled vehicles. Pickens is its founder and largest individual shareholder.

'Few Disagreements'