NEW YORK (AP) _ American investment companies describing themselves as socially responsible have expanded rapidly in the past few years, offering portfolios they say are devoid of companies that pollute, discriminate, build nuclear bombs or do business with South Africa.

At least five significant socially conscious investment funds are attracting billions of dollars from investors, a movement that analysts say has prompting attention from corporations and major investment firms.

''The social investment movement has been steadily growing since the early 1980s, but all of a sudden in the last few years it has experienced incredibly rapid growth,'' said Gordon Davidson, an officer of the Social Investment Forum, a Boston-based trade and investment association.

''As much as anything, it's finally providing investors an appropriate vehicle to express their ethical concerns,'' he said.

Figures compiled by the Council on Economic Priorities, a New York-based research group, show the amount of money managed by such funds jumped from $40 billion in 1984 to $100 billion last year.

Well-established Wall Street investment houses once ignored these types of investments, but now are attempting to accommodate them because of the enormous amount of money involved, Davidson said.

''We're getting a lot of brokers coming in for information, because they're getting pressured by their clients,'' he said. ''It used to be that the big brokers would not bother with social investing.''

The social investment funds agree that the catalyst for their growth has been the U.S. movement against South Africa's policies of racial separation.

More than 70 universities have ordered their endowment funds to divest from South African holdings. The governments of 17 states and 69 counties and cities have taken similar action.

''People just became aware they were investing in companies that were doing a lot of business down there, and they just didn't like it,'' said Rosalyn Will, a researcher for the Council on Economic Priorities.

Social investment funds vary in scope. Some, like the Dreyfus Third Century Fund in New York, evaluate corporate investments based on company policies regarding consumer protection, occupational safety and the environment.

Others, like the Pax World Fund of Portsmouth, N.H., have more stringent screening requirements, ruling out investments in nuclear weapons builders and other defense contractors.

One successful fund is Working Assets, a San Francisco-based money-market fund founded by eight people a few years ago with capital of $100,000. By April of this year, it was managing assets totaling $80 million.

''We know what we invest in: housing, education, energy conservation,'' said Carmen Wyllie, a spokeswoman. ''We do not invest in missiles or nuclear power, South Africa, toxic waste.''

Earlier this year, Working Assets started a Visa credit card subsidiary in cooperation with the State Street Bank of Boston, with an interest rate of 17.5 percent. More than 10,000 cards have been issued.

Every time a subscriber uses the card, a nickel is deposited into a fund and the proceeds will be donated to nonprofit organizations at the end of this year, said Laura Scher, chief executive of the subsidiary.

She would not disclose how much money is in the fund, but said ''we think it's going to be enough so people do take notice.''

Smaller though still successful is New Alternatives, an environmental investment fund based in Great Neck, N.Y. Begun in 1982 with $100,000, it now manages assets exceeding $1 million.

David Schoenwald, a New Alternatives founder, said the fund purchases stock in companies ranging from Owens-Corning Fiberglas Corp., because of its insulation projects, to Hawaii Electric, a non-nuclear utility.

Although such funds remain a relatively small element in the investing world, they contend that companies are beginning to take notice.

Partly because of this economic pressure, 10 large corporations signed the Sullivan Principles for fair labor practices this year, five reformed their policies on nuclear energy and the environment, and seven revised their policies on minority hiring, the Council on Economic Priorities maintained.

''Putting your money into positive investments can have an effect,'' said Davidson of the Social Investment Forum. ''Believe me, the companies are paying attention. They are very sensitive to these kinds of issues.'' Adv 09