Seemingly cheap "value" stocks and the mutual funds that buy them have led the stock market up from March lows.

But many professional investors believe that market leadership is poised to shift to "growth" stocks, those of companies with greater potential to expand earnings and revenue.

Distinctions in relative performance seemed pointless during the bear market, when shares of every type of company — small, large, growth, value — got crushed. In the rebound from the March 9 low, clearer patterns have emerged.

Small stocks have beaten large stocks, and among companies of all sizes, value stocks have beaten growth. For instance, funds holding small value stocks are up 74% (through Oct. 28), compared with a 58% increase for funds holding small growth stocks, according to Morningstar Inc. Funds holding large growth stocks are up 52%, the smallest advance among nine categories of diversified U.S. stock funds.

It is common for value companies, whose shares appear cheap compared with their earnings, revenue or book value, to lead the way out of a trough. During a severe economic downturn, share prices for the smallest, most struggling firms can collapse because investors sell shares of companies they fear will go bankrupt. "Many cheap value companies are cheap because people doubt their sustainability," says Ron Sloan , a senior portfolio manager at Invesco Ltd.'s AIM fund unit. When the economy starts to improve and it becomes clear that those firms won't go under, they can rebound sharply.

But many investors say that effect won't last. Small, risky value companies are unlikely to keep leading if a U.S. economic recovery remains weak. Without robust domestic demand, such companies may not perform well and will probably cede leadership to growth companies perceived to have the ability to thrive even in a lackluster economy. Technology, the classic growth sector, could benefit as companies try to maximize productivity in a "jobless" recovery.

"If we're in a tough world where revenues are hard to come by, where you need to sell to emerging markets to find growth, bigger companies will benefit more, and old-fashioned growth businesses" will begin to outperform the value companies that have led the bounce, says Mr. Sloan. Tech giants such as Intel Corp., Cisco Systems Inc. and Motorola Inc., which earn a large portion of their revenues overseas, along with health-care firms like Medtronic Inc., could be winners, he says. All are holdings in the AIM Charter fund for which he is lead manager.