There's a wave of company builders who are starting businesses when they're barely out of college, even high school. It's hard to quantify the phenomenon;no one keeps track of the numbers. But the ripples are starting to show up in the Inc. 500: In 1992, 30 of the 500 fastest-growing companies in the UnitedStates were headed by people 30 years old or younger.

Starting a company when you're in your twenties presents special challenges. "People had a hard time taking me seriously," recalls Bud Prentice of AppliedComputer Technology, in Fort Collins, Colo. "A supplier once asked me, 'Where are your parents?" For many, a big hurdle is money. Few youngentrepreneurs have personal savings or collateral to borrow against ("What was the bank going to take, our stereos?" asks John Chuang of MacTemps, inCambridge, Mass.), which means being crafty at bootstrapping or persuading family members that the business is a decent investment.

Still, most young entrepreneurs believe that they're at the best age to launch a business. Many don't have a spouse or children to worryabout when they're logging 80-hour weeks. Sharing apartments with roommates or even living at home with parents keeps overhead low. And if the businessfizzles, when else is it as easy to pick up the pieces? "The worst thing that would happen," figured Bob Roscoe of MBS Communications, in Cheshire,Conn., "was that I'd have to go out and get a job like other people."