Government lawyers, probing whether the ex-boss of American International Group Inc. and the former head of the New York Stock Exchange tried to manipulate AIG share prices in 2004, ran into a wall in 2005.

Richard A. Grasso, former NYSE chief executive officer, invoked his Fifth Amendment right against self-incrimination about 160 times when asked about his own actions and those of AIG Chairman Maurice Greenberg, according to a record of the proceedings released last week.

The questions by U.S. Securities and Exchange Commission attorneys were part of a probe into oversight of exchange specialists, who manage floor trading of stocks. The SEC has accused some specialists of profiting by putting their trades ahead of customer orders.

According to the transcript, the government lawyers focused in large part on the dealings of Grasso and Greenberg with Spear, Leeds & Kellogg Specialists L.L.C., New York, the firm that handled AIG stock.

Grasso was asked if he had not paid personal visits on the floor of the exchange to Speer traders to tell them of Greenberg’s “unhappiness” with their failure to prop up AIG’s share price.

He also was asked whether he had “yelled at” a Spear trader “for not living up to Greenberg’s expectations,” and threatened to remove Spear as AIG specialist.

Grasso was quizzed about Spear’s buying $17 million of AIG stock that was put in a special account in 2000.

“Isn’t it true that you knew Spear established this investment account in an attempt to appease Greenberg?” Grasso was asked. Grasso–as he did with all questions concerning AIG and Greenberg–invoked the Fifth Amendment.

The SEC transcript material was released June 14 by Justice Charles E. Ramos in New York Supreme Court in Manhattan, a county-level jurisdiction, where New York State Attorney General Eliot Spitzer has brought suit against Grasso over Grasso’s $190 million compensation package.

The transcript was part of the lawsuit, and Grasso’s attorneys argued unsuccessfully to keep it sealed.