The Bank of America, based in San Francisco, is about to become the first commercial bank in the nation to sell shares in a pool of its residential mortgages.

The securities will be sold in $100,000 denominations to institutional investors such as pension funds and insurance companies. Permission was granted last week by the Comptroller of the Currency.

By selling directly to the public, Bank of America expects to get a better return than it now can by selling its mortgages at a discount to quasi-governmental bodies like Fannie Mae. In return, Bank of America - a commercial institutional heavily into home mortgages - expects to be able to return more money to the residential mortgage market.

This is seen as a means of combatting red-lining by Robert Bloom, acting Comptroller of the Currency. The strategy is that investors will be more interested in the institution backing the securities - the Bank of America - than the geopraphic location of the mortgaged property - the Watts area of Los Angeles, for example.

The move is also viewed as a challenge to Fannie Mae's sluggishness in the inner city market, a position often criticized by Bank of America vice president Alan E. Rothenberg.