Freddie Mac Chief Executive Officer Richard Syron stood before investors at New York's Palace Hotel in May last year lauding his company's "cautious" avoidance of the subprime-mortgage crisis.

What Syron, who was ousted last week, didn't say was that Freddie Mac had been gorging on subprime and Alt-A debt.

While it and the larger Fannie Mae bought the safest classes of the mortgage-loan pools, Freddie's purchases totaled $158 billion, or 13 percent, of all the securities created in 2006 and 2007, according to data from its regulator and Inside MBS & ABS, a Bethesda, Maryland-based newsletter used by Federal Reserve researchers. Fannie, which was also seized by the US on Sept 7, bought an additional 5 percent.