Opponents of impact investing say these investments require people to sacrifice returns. That can be the case. Najada Kumbuli, who leads a gender investing initiative at the Calvert Foundation (which is separate from the mutual fund company Calvert Investments), said the foundation had a $20 million fund that allowed the 900 investors in it to pick the length and return of their investments. A one-year investment will return one-half of 1 percent, while a 10-year investment will yield about 3 percent a year.

“Paying back investors full principal and interest is important,” she said. “But so, too, is the data. It’s not just that we lent to 10 organizations but also, how are we shaping the sector and how are we investing in women?”

Proponents say comparable returns can be achieved, and when they are — and even when they’re missed — there is the added benefit of helping an organization trying to achieve a goal beyond maximizing profit.

Ms. Farrar-Rivas said she had a client who had invested nearly $20 million in impact investments.

Some of the client’s investments are expected to return 6 percent over seven to 10 years, while others may be closer to 1 or 2 percent — and require much more time to manage.

Yet the client still believes that comparable returns can be achieved, Ms. Farrar-Rivas said. To test a hypothesis, the client created a $9 million “women’s inclusion portfolio” that is evenly divided among index funds, public stocks and bonds, and direct, private equity-like investments.

The problem with impact investing is often that there are not enough opportunities for direct investment or the ones that are available are small and take a lot of time to assess.

Benjamin Schmerler, a director of Root Capital, which has been investing in small agricultural businesses in Latin America and Africa, said it had made $900 million in impact investments since 1999. The money, in some 1,800 deals, has reached 5.2 million households and 570 borrowers. But to do this, the firm employs over 140 people.