American International Group is the only Fortune 500 company that has a faster revolving door than either HP or Yahoo! After 17 years at the helm, Hank Greenberg stepped down in 2005 and was replaced by Martin Sullivan. But in 2008, the company ran smack into the financial crisis. Short of cash because it guaranteed so many mortgage-backed securities that went sour, the company had to be bailed out by the Federal Reserve and the US Treasury. Mr. Sullivan resigned in 2008 and was followed by Robert Willumstad, who was forced out by the federal government that same year. Former Allstate President Edward Liddy took over until he retired in 2009. Ever since, AIG has been guided by Robert Benmosche, who has continued to sell off assets to pay off the federal loans it received.
"The average CEO tenure is six years," says Mr. Kaplan. Having four CEOs in that time – let alone five – is highly unusual, he adds.
