The turmoil in the stock market is beginning to have an impact on some organizations in the nonprofit sector, with at least one large philanthropist having lost his regular job and others predicting a drop in fund-raising if the downturn worsens.

The chairman of the Joseph Papp Public Theater, Warren Spector, was ousted earlier this month from his job as co-president of Bear Stearns & Co. Inc. after the investment bank lost billions of dollars when two hedge funds were forced to close. Mr. Spector has been the theater’s chairman since June 2005 and a spokesman said there are no plans for anything to change in the near future.

“It’s hard not to get caught in the downdraft structure,” the UJA Federation of New York’s chief financial officer, Irvin Rosenthal, said. “August is not going to be pretty.”

The credit crisis and the stock market turmoil are having a preliminary impact on the nonprofit sector and concern is growing that fund-raising could be hurt if the downturn continues to gain steam.

The full extent of any impact on the sector will be difficult to gage until year-end, when the bulk of donor giving occurs, experts say.

“It’s hard to know after a month or so of volatility what’s happening. But if the current volatility were to continue or if the markets were over the course of the year or end of the year to be in a down position, philanthropic giving is going to react in a similar way,” the chairman of the GivingUSA Foundation, Richard Jolly, said. “What we’re likely to see is an overall decline with some exceptions at organizations where the need is well articulated.”

Organizations are hoping that even if donors feel the impact of losses on Wall Street, the unprecedented profits they have earned during the recent boom market will soften the blow. In addition, many nonprofit organizations have prepared themselves for this moment, diversifying their investments and revenue sources, and lining up donors who have demonstrated they will step up in times of need.

Early solicitations at the UJAFederation’s Wall Street division have been “not at the level they were last year but quite respectable,” a senior vice president at the organization in charge of fundraising, Paul Kane, said. The UJA Federation’s endowment has been growing, aided in part by the $103 million sale last year of the retail space at its headquarters building on Lexington Avenue and 59th Street. The nonprofit’s investment strategy is “very conservative, aimed at protecting assets regardless of what’s going on in the market,” Mr. Rosenthal said.

“I think we’ll fare very well because our board and our staff have worked hard to make the institution financially resilient,” the president of the New York Botanical Garden, Gregory Long, said. “I’m not looking forward to a recession, but if we had one I think we would weather it and maintain our core services.” The last time there was a market downturn, in 2001, the Botanical Garden cut or postponed some special exhibitions, and lost 8% of its staff. It has only recently completed restaffing all of its employees.

Many nonprofits tow a conservative line, providing them some protection to market turmoil. “Our exposure to subprime is .00000 something or other. We don’t take risky bets that would get us into those types of situations,” a managing director at the nonprofit endowment management firm Commonfund, Jud Koss, said. His firm handles $42.5 billion on behalf of 1,600 nonprofits including foundations, universities, hospitals, and museums.

When times get bad, foundations will often increase their payouts to their nonprofit clients, or so-called grantees. The increased payout can help mitigate the loss of individual donor contributions or, in a time of greater need, it can help a nonprofit manage its larger expenses.

“We increased our payouts in 2001,” the program officer for the Nonprofit Sector Support Program at the Surdna Foundation, who is also chairman of the New York Regional Association of Grantmakers, Vincent Stehle, said. Given the challenges nonprofits were facing, “we felt it was worthwhile to go a little beyond the minimum requirement, that we could afford it in the long term,” he said.

The nonprofit watchdog group Charity Navigator tracks whether revenue growth and program expenses are growing. “Exactly in the instances of market volatility, it’s important that charities have rainy day funds and that they are financially stable,” the vice president of marketing at Charity Navigator, Sandra Miniutti, said.

Institutions in the midst of large capital campaigns may face retrenchment. “If big pledges have been committed, but the market turns, a university might wind up renegotiating the terms of the pledges, or scaling back the scope of the campaigns, cutting out a building here, a faculty chair there,” the executive director of New York University’s George Heyman Center for Philanthropy and Fundraising, Naomi Levine, said.

That there are more American billionaires than ever, however, could serve as the ultimate recession cushion. “I’m not sure how a recession affects a billionaire. If I don’t have a billion, I could have $800 million, and I could still give to philanthropy,” Mrs. Levine, who ran New York University’s fund-raising for more than 20 years, said. As for the non-billionaires in charge of fund-raising, she said: “I would follow the market and I would try to persuade myself that it’s going to settle and it will be all right. … But at night when I go to sleep, I’d be worrying.”