Institutional investors grilled GM on Perot buyout.

A group of investors holding more than 7 million shares of General Motors stock demanded that GM explain further its $700-million buyout of Texas billionaire H. Ross Perot and his ouster from the GM board. “GM has a lot of explaining to do,” said Harrison Goldin, the New York City comptroller and co-chairman of the investor group, the Council of Institutional Investors.