Lawrence Summers, President Barack Obama's top economic adviser, Friday expressed doubt that government-controlled mortgage finance giants Fannie Mae (FNM) and Freddie Mac (FRE) would be recreated in their old mold.

Summers, a critic of the companies when he served as Treasury secretary under President Clinton, said he expected a different model for U.S. mortgage finance would be created, marked by a "sharper cleavage" between the public and private roles.

"I think it is very unlikely that the answer lies in going back to the past," he said at a panel discussion in Washington.

-By Jessica Holzer, Dow Jones Newswires, 202-862-9228; jessica.holzer@dowjones.com