Geithner: Glory days over for Fannie and Freddie

"It is not tenable to leave in place the system we have today," he said. "We will not support returning Fannie and Freddie to the role they played before conservatorship, where they fought to take market share from private competitors while enjoying the privilege of government support."

Geithner's comment kicked off a conference at the Treasury on housing finance.

The meeting will tap the opinions of citizens, consumer advocacy groups, economists, investors, lenders and many others on how best to reform housing finance.

The Treasury last April sought public comment on housing finance and received hundreds of responses. Today's conference is the next step in the Treasury delivering to Congress a housing finance reform proposal by January 2011.