Life's so hectic, I feel like a bouncing ball," says Elisabeth Claiborne, 50. No wonder. Five years ago she, her husband and two partners started Liz Claiborne Inc. with $250,000 borrowed from friends and family. Today it is the hottest sportswear firm on Seventh Avenue, a $100 million-a-year "growth company" whose stock has been traded over the counter since last summer. Its price jumped from $19 to $31 in the first six months, and last week it was selling at $25 in a declining market. (No other individual designer's stock is sold publicly; Calvin Klein Jeans, Halston and other big labels are subsidiaries of conglomerates.)

What made investors cotton to an apparel company despite the industry's boom-or-bust reputation? "Our concept," answers Liz. In the mid-'70s she decided the then emerging class of professional women needed their own look. What Claiborne came up with was a small collection of classic, well-made clothes with a contemporary twist: pleated wrap skirts, lightweight lumberjackets, culottes and brilliant-hued mohair sweaters—all designed to coordinate. Although her clothes did not fit the formal "Dress for Success" mold, they were not too far-out to be worn to the office. "The working woman," notes Claiborne, "doesn't have to dress in a gray flannel suit anymore."

Since then her company has spun off in many directions—jeans, shoes, accessories and, most recently, dresses. What has remained constant is the price of the clothes: from $22 for cotton shorts to $150 for wool jackets.

The key ingredient in the line is Liz herself, who is president and chief designer; her husband, Arthur Ortenberg, is in charge of merchandising. Born to a socially prominent New Orleans family, Liz lived in so many places (primarily Brussels, New Orleans and New York) that she never completed high school. "Being dragged around to museums and cathedrals" by her banker father sparked an early interest in art, which developed into a love of fashion. Nevertheless, he ruled out a career in the garment business for Claiborne and instead sent her to study painting in Nice at the age of 20.

She returned to the U.S. and in defiance of Dad launched herself on Seventh Avenue on her 21st birthday as a sketch artist and model. That same rebellious year she married a Time-Life Books designer, Ben Schultz; they broke up five years later, shortly after she met Ortenberg, now 54. He was also married at the time. After difficult divorces and years of psychoanalysis for each, they were wed in 1957.

During 16 years at giant Jonathan Logan, Liz set out to "make moderate-priced clothes that would cater to the mass of working women." Buoyed by her success, she decided to strike out on her own. Since then the business has kept the Ortenbergs and partners Leonard Boxer (vice-president in charge of production) and Jerry Chasen (marketing) working 15 hours a day. "The perception on Wall Street," explains Ortenberg, "is that apparel firms are run by guys named Manny and Irving—seat-of-the-pants guys who are not of managerial caliber." Before going public, the four partners launched a five-city blitz with Merrill Lynch to convince potential investors of their stability.

Liz and Arthur live in a sparsely furnished all-white Manhattan apartment, but weekends they escape to a year-round house on Fire Island. (They both have children from their previous marriages: he, a son and daughter, aged 30 and 28; she, a 27-year-old son, who is a jazz guitarist.) The Ortenbergs pocketed $2.6 million when the company went public in June, but aren't slowing down a bit. "You never worry that someone's home saying, 'What the hell's keeping you so late?' " explains Liz. "We both know."