Compaq

Compaq was the fastest company in American history to reach $1 billion in revenue, doing it in just five years. Founded by three former Texas Instruments engineers who sketched their first product on a placemat at a Houston pie restaurant, Compaq reverse-engineered IBM's BIOS and built the first legal IBM PC clone.

That move cracked open the entire PC industry. Compaq proved you didn't need IBM's permission to build a PC, and a thousand clone makers followed. By 1994, Compaq was the world's largest PC manufacturer. In 1998, it acquired Digital Equipment Corporation (DEC) for $9.6 billion, one of the biggest tech acquisitions of its era.

But Compaq couldn't compete on price with Dell's direct-sales model. Revenue declined, the stock cratered, and HP acquired Compaq for $25 billion in 2002 in a controversial merger that then-HP CEO Carly Fiorina pushed through over the objections of HP's founding families. The Compaq name was phased out within a few years.