American International Group Inc. said late Wednesday that Harvey Golub resigned as chairman, citing a bad working relationship with CEO Bob Benmosche.
Robert S. Miller was named to succeed Golub, effective immediately.
In a resignation letter released by AIG, Golub said Benmosche informed the board of directors that the two executives' working relationship is "ineffective and unsustainable."
Golub said he elected to resign because he believes it is easier for the board to replace the chairman than the CEO, given that the company is in the middle of a corporate restructuring and developing an exit plan from government control.
Miller, 68, was elected to AIG's board last year. He serves as chairman of MidOcean Partners.
Golub's exit comes a day after a report suggested AIG's board was considering an initial public offering for its Asian life insurance unit, AIA.
Last month, a watchdog panel raised new doubts over the likelihood taxpayers will be fully repaid for the government's $182.5 billion bailout of AIG.
Much of the rescue money went to meet the company's obligations to its Wall Street trading partners on credit default swaps.
The company has been selling assets in an effort to raise money to pay back the government.
AIG shares slid 46 cents to close at $37.53.