Key differences in the legislation to tighten regulation of Fannie Mae and Freddie Mac as approved by the House and by the Senate Banking Committee:

* Limiting the companies' investment portfolios:

House -- The companies' new regulator could require the mortgage finance giants to adjust their portfolios to keep the companies solvent if circumstances warrant. The regulator also could require portfolio changes for other reasons. "If you don't see it on our list, Mr. Director, do it anyway because we are giving you the authority," said sponsor Rep. Richard H. Baker (R-La.).

Senate -- The companies would be allowed to keep only certain types of assets. The new regulator would oversee a gradual sell-off of prohibited assets. The Bush administration and Federal Reserve Chairman Alan Greenspan favor this approach as it better ensures that the companies' portfolios would shrink.

* Housing fund:

House -- The companies would have to set aside 3.5 percent of their profits for two years, then 5 percent for the next three years, to finance low-income housing. In the first two years, projects in hurricane-damaged areas would receive priority. Groups engaged in voter registration and get-out-the-vote efforts could not apply for the money.

Senate -- No such fund.

-- Annys Shin