(FORTUNE Magazine) – Not so long ago, owning Reebok shoes--much less Reebok stock--was totally uncool. But in the past two years--ever since CEO Paul Fireman returned to the top job, really--business has been on a tear. Gear endorsed by basketball star Allen Iverson has been a slam-dunk. Reebok penned exclusive deals to market NBA and NFL wear and wowed the Street by deftly cutting costs. It's been a killer combination: Since the beginning of 2000 the stock has soared nearly 300%, making the perennial also-ran the best-performing stock on the S&P 500 last year. Investors can't help but wonder: Does the No. 2 shoemaker still have room to run?

It'll be a tough slog. "This industry has been flat as a pancake for nine years," says Wells Fargo Van Kasper analyst John Shanley. That means Reebok, Nike, Adidas, and the rest are locked in a tooth-and-nail battle for market share. Nike remains the industry powerhouse, with 37% of the market--down considerably from the 47% it controlled in 1997. Reebok, meanwhile, has pumped up its portion over the past year from 12% to around 15%.

The course may be uphill from here. Analysts say Nike lost its footing by focusing too much on the high-end market and not enough on the middle--shoes selling for $60 to $80. But Nike's new lines are getting early raves, as are those of Adidas and New Balance. "Reebok has good things," says Shanley, "but it's not as if they're going to have the market to themselves like they've had for the past nine months."

Add to that the pressure from retailers like Foot Locker, which Shanley says has begun extracting "significant price and promotional concessions from its vendors." Already Reebok's margins have declined for four straight quarters. And there's only so much cost cutting it can do.

All of which means investors looking to cash in on this turnaround may be too late. At $32, the stock is close to its 52-week high of $36 and trades for nearly 16 times 2002 earnings (vs. the industry average of 13).

Of course, meeting Wall Street's challenge may be the lesser of Reebok's hurdles. The toughest crowd is, inevitably, the style set. "From a fashion point of view, Reebok is right up there," says Judy Gordon of TheTrendReport.com. "But Nike's still the leader."

--Lee Clifford