NEW YORK(Reuters) - Giving back to their communities has always been a challenge for pro athletes who get rich quick because they tend to lose the money even more quickly. But even those who manage to build a substantial amount of wealth have a hard time using it charitably in a way that truly has a long-term effect.

FILE PHOTO -- March 11, 2016; Los Angeles, CA, USA; Los Angeles Clippers guard Chris Paul (3) moves the ball up court against New York Knicks during the second half at Staples Center. Gary A. Vasquez-USA TODAY Sports/File Photo

Some celebrity athletes are turning to “impact investing,” a growing niche of do-gooder strategies that aim to put money toward charitable causes but that would otherwise lack support. Fund managers, of course, also aim to generate income in the process.

The Turner Multifamily Impact Fund, a private-equity style vehicle focused on preserving affordable housing, has lately drawn financial support from NBA All Star Chris Paul.

He joins former World No. 1 tennis player Andre Agassi and Basketball Hall of Famer Magic Johnson, who have invested in other funds and projects run by the parent company, Turner Impact Capital and its founder, Bobby Turner. Their contributions work with dollars from hedge fund billionaire Bill Ackman, the Rockefeller Brothers Fund and actress Eva Longoria.

In an interview with Reuters, Paul said he was frustrated by the feeling that giving away his own millions only “put a Band-Aid on a situation.” As a point guard for the Los Angeles Clippers, he has earned money not just from the 5-year, $107.3 million contract he signed in 2013, but also from lucrative endorsements for companies like Nike and State Farm Insurance.

Paul is worth an estimated $30 million, according to Forbes.

“We were doing basketball courts here or there, we’d always do giveaways during the holidays, and we did 10 computer labs,” Paul said, referring to a few of the projects the Chris Paul Family Foundation has organized for disadvantaged kids. “But at times, philanthropy can be frustrating.”

Whether impact investing is more successful than pure charitable giving is unclear.

Unlike simply giving money away, impact investing does provide a return, which could enable philanthropists to sustain or grow their charitable giving. But broadly speaking, impact funds have delivered lower returns than straightforward stock or bond market indexes, according to data from the Global Impact Investing Network, a trade group.

The funds also charge higher fees than traditional investment tools like mutual funds and index funds, because of the amount of work that goes into the investments, such as scouting apartment complexes for affordable housing funds.

But impact investing proponents argue that analyzing financial returns alone is misguided.

That is because they are more concerned with whether their money is achieving an outcome, like preserving affordable housing in a gentrifying neighborhood, than whether the investment generates a certain profit. Around 40 percent of impact investors polled by Global Impact said they seek below- market returns.

Counter-intuitively, funds that deliver below-market returns may be the most successful because it indicates they would not otherwise receive funding, said Paul Brest, a professor at Stanford University who teaches courses on impact investing.

“That’s the sweet spot for impact investing, because by definition, ordinary investors are not going to invest in that,” he said.

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There were over 400 impact investing funds and products, with $31 billion in committed money, in 2015, the latest year for which data is available from Global Impact.

Run by former hedge-fund manager Bobby Turner, the Turner Multifamily Impact Fund launched in 2015 and raised $264 million in capital. It has so far acquired nine garden-style apartment complexes on the outskirts of cities like Dallas, Austin and Las Vegas, according to the fund’s website.

“We’re trying to give housing to people who make too much money for subsidized housing but do not make enough for luxury rentals or home ownership,” Turner told Reuters.

The apartments are mostly filled with tenants who earn up to 80 percent of an area’s median income, and rent is no more than 35 percent of a tenant’s salary.

To make the investment sustainable, Turner said tenant turnover must be kept low. The fund tries to do that by providing additional services like community watch groups, free tutoring and on-site clinics run by other residents who work in law enforcement, healthcare or education and receive half-price rent for running these programs.

At the Turner-owned Regency Pointe Apartments, a cluster of two-story red brick apartments 10 miles from Washington D.C., the typical tenant would earn $54,666 a year, according to U.S. Census data. Rent for a three-bedroom starts at $1,456 a month, according to the complex’s website.

The fund is aiming for 10 to 12 percent returns net of all fees over the next few years by keeping tenant turnover and insurance costs low. Turner’s firm does not disclose fees, but generally speaking, industry sources said similar, private equity-style funds typically charge annual management fees of 1.5 to 2 percent of assets, plus 20 percent of profits.

A benchmark generated by Global Impact Investing Network shows impact funds generated 5.58 percent returns over 15 years ending last June. The benchmark underperformed stock and bond market indexes across all timeframes it measures.

But Paul says that earning a financial return is essential to the fund’s success.

“That’s the fuel we need to bring in investors and reach even more communities and families,” Paul said. “When you combine a positive financial return with positive social impact, you can make a huge difference for people.