No, you're not seeing double -- or triple. The number of mutual funds run by co-managers is multiplying. But does such a move translate into multiplying returns?

During the past three years, the number of funds with more than one manager has jumped from 21% to 34%, according to fund tracker

Thomson/Wiesenberger

. But Wiesenberger's data don't suggest that the new approach has had much effect on performance.

The reasons that fund companies increasingly opt for tag teams aren't difficult to understand. In today's market, money managers garner salaries comparable to pro ball players, and often star status to boot. Like athletes, these managers often jump to other teams if a better offer comes along, leaving a fund with a gaping hole. By moving toward well-staffed funds and away from solo fliers, fund companies hope to provide the continuity investors crave, while preventing a fund from being too closely associated with one manager.

"If you named one person on the prospectus and the person left, the track record went with that person," explains Jacob Navon, managing director with

Warren International

, an asset management headhunter firm in New York. "Whereas if you have a team, both the formal track record and public perception is with the fund."

As an example, the

Scudder

family of mutual funds opted for team management a few years ago after defections following its merger with the

Zurich Kemper

funds. And

MFS

, which lost a few managers to hedge funds a year ago, has moved to replace them with a group of portfolio managers and analysts. However, the moves haven't exactly opened up the cash spigot: In the last year, Kemper has seen outflows, and MFS has taken in less money so far this year compared with last year.

Nevertheless, Navon says, team management benefits funds because "it eliminates the star system." He adds that team-run funds also pay their managers less if there are no standouts.

But none of this means investors should rush out to find funds with more than one manager. "We didn't see any proof that either one was better than the other in terms of performance," says Wiesenberger analyst Ramy Shaalan.

Indeed, not all shareholders see benefits. "If anything, having more people in a fund harms performance because with more people, there are more ideas," that could get in the way of stock picking, says Louis Stanasolovich, a financial planner with

Legend Financial

in Pittsburgh.

But Thomas Reilly, a managing director in

Putnam's

global equities division, says teams keep individual managers from veering off into uncharted investment styles. "Now our funds are style driven as opposed to star driven," he says.

Putnam adopted the team approach in 1984 when it reorganized its funds into pure style categories to prevent style drift. The approach encourages consistency in investment results, Reilly says. The funds won't be among a handful of standouts in any given year, but neither will they be stinkers. For the most part, the Putnam funds have performed in the middle of the pack.

The funds also tout their multiple managers to reassure investors. "We encourage our managers to travel so there's always a manager manning the desk," says Molly Cisneros, a spokeswoman with the

Invesco

funds in Denver, which adopted the method more than 15 years ago.

Some fund companies could have used a team in light of recent defections. When Frank "Quint" Slattery left two

PBHG

funds earlier this month, it took the company more than two weeks to decide how to fill his slot. The same thing happened at the company last year when Jim McCall made way for

Merrill Lynch

.

When Alex Cheung of

Monument's

(MFITX)

Internet fund left recently to start his own asset management company, there was no clear line of succession. The firm quickly brought in an outside manager.

Some problems arising from management stars who bolt run even deeper. When Ryan Jacob left his old charge, the

(WWWFX) - Get Report

Internet fund with

Kinetics

, it left former colleagues publicly bickering about who owned the impressive performance record since the fund was supposedly managed as a team.

Of course, even with a team, there's no guarantee that a fund can smooth over the rough patches. The

(NGTIX)

Nicholas-Applegate Global Technology fund has slipped in its rankings in the two months since manager Aaron Harris left the fund for

Villanova Capital

. Harris was the fourth member of the team to depart in nine months.

Even though singly managed funds may be on the decline, shareholders should be warned: In recent months, many of headhunter Navon's mutual fund clients have been inquiring about management team lift-outs. "That way they get to hold onto the track record," he says.