The Federal National Mortgage Association expects to write off $109 million in mortgage losses from foreclosures this year, Fannie Mae Chairman David O. Maxwell said yesterday.

The figure would be a record, topping last year's $87.3 million.

Maxwell, who disclosed the loss figure in a speech to security analysts in New York, said, however, that he is confident Fannie Mae "will be profitable this year" and next.

Fannie Mae, a congressionally chartered, stockholder-owned company, buys mortgages from lenders, thus providing them with money to make additional loans. The corporation suffered heavy losses in the early 1980s when interest rates rose rapidly, and recently has suffered -- along with most other mortgage-holders -- as foreclosure rates have soared on high-interest or gimmicky loans written during that time.

Fannie Mae recently announced a sharp tightening in its underwriting standards. Maxwell called this move essential to both his company and the mortgage-finance system as a whole, because home values are not rising rapidly enough to bail out troubled homeowners.

He has conceded that some buyers will not be able to obtain loans but said that is the price of a sound system.

"You bet there are some marginal buyers who will not be able to qualify for a loan who formerly would have," he said in a recent interview. "And that's exactly what we intended to have happen."

Maxwell argued, however, that the actual number of such people who are in the home market is relatively small.