The company also said that Howard Smith had been replaced as chief financial officer by Howard Bensinger, previously senior vice president, treasurer and comptroller.

Reacting to the AIG announcement, A.M. Best Co. said it has placed its "A-double-plus" financial strength ratings for AIG member companies under review with "Negative" implications. Standard & Poor's Ratings Services in New York also said it placed its "triple-A" long-term counterparty credit rating on CreditWatch with negative implications.

Meanwhile, Moody's Investors Service lowered its outlook for AIG's debt ratings and financial strength ratings of its property-casualty, life and mortgage insurance and reinsurance segments to "Negative" from "Stable." Fitch Ratings went a step further, downgrading its long-term AIG debt ratings to "double-A-plus" but with a "Stable" outlook.

According to the Oldwick, N.J.-based A.M. Best, the ratings are under review because of the delay in the annual report filing, the premature retirement of two top senior executives and numerous regulatory inquiries.

Nonetheless, A.M. Best sounded optimistic about AIG's future without Mr. Greenberg at the helm. The firm said AIG's operating fundamentals are sound and that there is significant management bench-strength among top AIG leaders to pick up the slack.

S&P credit analyst Grace Osborne in a conference call took note of the Greenberg and Smith departures and said the regulatory scrutiny from the New York Attorney General's Office and Securities and Exchange Commission that AIG is facing "has not abated."

She said the CreditWatch status will be resolved after AIG files its delayed 2004 annual report.

S&P is not expecting AIG to restate any prior-year financial results, Ms. Osborne added, but "nevertheless, we really must allow for the possibility. We cannot analyze any credit implications as restatement occurs until the 10-K [annual report] is filed."

But even if S&P takes further actions, it is unlikely that either the AIG holding company or its operating insurance companies would fall below the "double-A" range, Ms. Osborne said.

Fitch Ratings in New York so far is the only major firm to cut AIG ratings. It downgraded its long-term issuer rating and unsecured senior debt obligations to "double-A-plus" from "triple-A."

Fitch said AIG has been pressured by recent government probes regarding its business practices and that "Fitch believes uncertainties and disruptions created by these events are inconsistent with the highly conservative and stable profile required of a company assigned a 'triple-A.'"

Commenting on Mr. Greenberg's departure as CEO, "There will certainly be an adjustment period for AIG," Fitch Managing Director Julie Burke told National Underwriter. "He's been the leader for nearly 40 years. But AIG has a deep management team, so while Mr. Greenberg's leaving will have an impact, the company will just adjust for that and move on."

As for AIG's new leader Martin Sullivan, S&P said it feels the executive is well qualified to meet the challenge. "Mr. Sullivan has been in the organization?he understands the insurance world well, how it works and the AIG culture. He has the appropriate leadership quality," said S&P's Ms. Osborne.