Maurice "Hank" Greenberg resigned from the board of American International Group Inc, the insurance company he led as CEO for nearly 40 years and built into one of the world's largest.
The resignation announced late on Wednesday was effective immediately, according to Greenberg's four-sentence resignation letter.
"My decision to resign now results from my inability to receive information regarding the company and its operations necessary to fulfill my fiduciary duties," he wrote. "I wish the employees of AIG every future success."
A spokesman for Greenberg's legal team did not immediately return a call seeking comment.
AIG's board forced Greenberg, 80, to relinquish his posts as president and CEO on March 14, and he retired as the company's chairman two weeks later.
Greenberg had previously said he would not stand for re-election as a director, and in April the company named two new outside members to its board.
New York regulators have filed a civil lawsuit against AIG, Greenberg and former chief financial officer Howard Smith, saying they orchestrated an accounting scheme that made AIG's financial picture appear brighter than it was, misleading investors and regulators.