After two decades in investment banking, Lamb felt an urge to do something different. She decided to take a paid sabbatical from Lazard and spent a year chairing the board of the New York Women’s Foundation, which piqued her interest in the nonprofit sector. She soon realized she could apply her banking skills and experience to nonprofits, the number of which were continually increasing despite a chronic lack of funding.

“I looked at the market and saw I could fill a need,” says the 62-year-old Lamb.

After adding more clients by referral, she founded Lamb Advisors in mid-2003 and discovered that corporate refinancing in the public sector is not that different from private-sector deals. In both cases, she has to present strategic alternatives to her clients, get buy-in from each organization’s board, find the right partner, and help negotiate the terms. According to Lamb, the main difference is timing: Nonprofit mergers take longer to execute because there’s no market pressure or potential competitors lurking in the background, as in the private sector. In addition, nonprofit executives don’t have the huge financial incentives to merge that private-sector execs often have.

Lamb’s first client, back in 2002, was the Creative Arts Team, which uses live theater to engage public school children. It needed to spin off from New York University, its sponsor and host for nearly 30 years. When N.Y.U. decided to end its sponsorship, C.A.T. asked Lamb to step in as transition leader. She contacted seven colleges and universities to gauge their interest in sponsoring C.A.T., and eventually the City University of New York, which saw a fit with its own public education goals, agreed. After supervising the group’s moving day, Lamb went on to oversee C.A.T.’s hiring of a head of development and a new C.F.O. and helped with its adjustment to a smaller revenue stream.

C.A.T. paid for Lamb’s services out of a five-figure-per-year grant from the United Way. These days, Lamb typically charges a low- to mid-five-figure fee per transaction if she can gauge the length of a project in advance. Otherwise, she charges $200 an hour.

Despite the considerable pay cut she has taken to pursue her new career, Lamb says she “misses nothing” about the private sector. And she doesn’t anticipate a shortage of work anytime soon. “As hedge fund, private equity, and investment banking money continues to stream into the nonprofit sector, it’s changing the nature of what the donor is asking—that is, ‘How are you spending my money and could you spend it more efficiently?’ ” Lamb says. That dynamic, plus the prospects of an economic slowdown causing a dip in funding, means more nonprofit mergers and acquisitions are likely in the offing.