Domini did not invent socially responsible investing. Shareholder activism grew up during the Vietnam War and the anti-apartheid struggle. Today some 150 mutual funds screen out politically incorrect companies. But more than anyone, Domini made ethical investing a mass-market option. Ten years ago, with two partners, she set up the Domini 400 Social Index, a benchmark for responsible portfolios. Its companies must pass muster on 140 issues, ranging from toxic-waste fines to diversity in top management. Yet Domini has kept pace with the S&P 500—a feat managed by fewer than a third of other mutual funds.

"Before, people would just carve out evil companies," says John Biggs, head of TIAA-CREF, the pension-fund giant, which launched its own social fund. "Amy brings investment discipline with social concerns." Domini's latest crusade: persuading the $7 trillion U.S. mutual-fund industry to post shareholder-resolution votes on its websites. "It's outrageous that managers are not telling investors how they vote," says Domini. "The small investor wants to fatten her wallet, but she also wants to breathe clean air and work in a safe environment."