11:21 AM ET 7/27/10 | SAN FRANCISCO (MarketWatch) -- Fannie Mae and Freddie Mac jumped in morning action on the over-the-counter bulletin board Tuesday after the Obama administration said it's organizing a conference on the future of the U.S. housing finance system for Aug. 17. "The future of our housing finance system is critical not only to our economic recovery, but also to millions of American homeowners in every corner of our country," Treasury Secretary Tim Geithner said in a statement. The White House is working on a housing finance reform proposal for delivery to Congress by January 2011. Fannie shares jumped 21% to 33 cents, while Freddie gained 16% to 36 cents.