(FORTUNE Magazine) – American International Group CEO Maurice "Hank" Greenberg, in a May 1 bulletin that beat his 77th birthday by three days, announced a succession plan so vague it could have been Joe Torre saying he would field nine Yankees. Undaunted, a knot of reporters sat in Greenberg's office on the day of the news and pressed for specificity. "When will you retire?" asked one reporter. "It ain't going to be ten years from now!" said Greenberg. "Well," said the reporter, eyeing his fit, hale, and intimidating subject, "does that mean it will be less than ten years from now or more than ten?"

Greenberg didn't bother to answer. But his next words were, "I had a great-grandmother who worked until she was 108 and then died in an accident." (Asked later about this remarkable woman, Greenberg said she came to the U.S. from Russia when she was in her late 80s and, until her death, sold "odds and ends" from a stand on the street.)

The reporters never pinned down Greenberg as to when he would retire or who would succeed him. But those details probably don't matter. What does is that Wall Street got some answers it has been frustratedly wanting: There is a succession plan, and the autocratic Greenberg, so he says, has even let his board know what it is. Analysts would clearly be horrified to get a different kind of news: any intimation that Greenberg is preparing to quickly step down from running this awesomely complex company. Says Alice Schroeder of Morgan Stanley, who has a buy recommendation on AIG: "What investors really want is for Hank to become immortal."