To a great extent, all actively managed equity mutual funds have benefited from the stock market rally over the past three months. Fund inflows have rebounded dramatically and stock prices of the asset management companies themselves have roughly doubled since Mar. 9. But enthusiasm toward stocks has cooled in the past two weeks as the markets more carefully weigh the considerable obstacles that the U.S. economy needs to surmount before it can return to health.

While the pace of money flows into equity mutual funds seems to have picked up in June from April and May, that's probably a bearish sign for stocks, according to TrimTabs Investment Research in Sausalito, Calif. That's not only because the amount of cash on the sidelines has been reduced, but because mutual fund investors tend to invest heavily in the late stage of rallies, says Conrad Gann, president of TrimTabs.

Daniel Fannon, an analyst at Jefferies (JEF) in San Francisco, sees all mutual fund managers benefiting from the positive momentum in equity markets of late. The May data for net inflows to mutual funds show that when investors piled back into equities as the rebound from early March continued, they didn't make much effort to distinguish between good and bad asset managers, he says.

"That's not sustainable, even if [equity] markets are flat from here" over the next six months, he says. "People will be choosey with where they're putting their money. There will be greater focus on relative performance, on one-, three-, and five-year numbers."

second-quarter operating margins Fannon expects certain asset managers with superior returns year-to-date to gain market share as investors start to reward better performance. Among the likely winners, Invesco (IVZ) stands out as a result of how well it performed on a relative basis in 2008 and even in the early months of 2009. Waddell & Reed (WDR) should attract new money, given the superior returns earned by its Ivy Asset Strategy Fund (WASAX) and Ivy Global Natural Resources Fund (IGNAX) so far this year. Janus Capital (JNS) has a broader range of funds that have done well this year and there are some T. Rowe Price (TROW) funds with impressive returns as well, he adds.

Another way to differentiate these stocks will be to compare operating margins in second-quarter earnings, says D.J. Neiman, an analyst at William Blair in Chicago. "The firms have done head count reductions of 10% to 12% to right-size their expense bases to current market reality levels and revenues levels," he says. "We'll see how quickly operating margins can snap back since moving from the lows" earlier this year, he says.