While apparel companies such as Banana Republic and J.Crew have spent the past few years closing stores, reducing inventory and tweaking product lines in an effort to reconnect with fleeing customers, menswear maker Peter Manning NYC has been growing steadily by focusing on an underserved segment of the population: men who are no more than 5 feet, 8 inches tall.

The sportswear line's sales have doubled annually since it launched six years ago as an online brand. The company does not disclose its revenue, but it did reveal that e-commerce sales reached eight figures last year. In step with the brick-and-mortar trend of Rent the Runway, Warby Parker and other successful online fashion and accessory retailers, Peter Manning in February 2017 opened its first retail location: a fit shop in the Flatiron District.

The company in June announced a new partnership with social media influencer Brock McGoff, founder of The Modest Man, a mens' lifestyle and fashion blog and YouTube channel with 130,000 subscribers. McGoff is managing Peter Manning's online content, and he assists with product development.

Peter Manning, which focuses on offering its customers work clothes and casual wear in just the right sizes, has trademarked its tagline: "For the not-so-tall guy."

"The fashion industry designs for a certain height, and if you're outside of that, you're out of luck," says the company's 5-foot-9 chief executive, Jeff Hansen, who adds that for most of his life, he wore jeans that didn't fit properly.

"Nobody had invented an inseam shorter than 30 inches, so I always thought I wore a size 30," he said. But when he moved to Italy in 2007 for a job managing a luxury brand, he noticed how much better some clothing fit him. "In the Mediterranean," he said, "they're more about our guys' sizes."

Despite the high revenue potential, not-so-tall guys have remained under the radar of most clothing retailers. Online men's clothing is an estimated $20 billion industry, according to market research firm IBISWorld. And 1 in 3 men in the United States is 5 feet, 8 inches, or shorter, based on 2011 U.S. census data.

Petite sizing for women has existed for decades, but men have had no equivalent. That makes Peter Manning's sweet spot a nearly $7 billion opportunity.

New York City is the company's biggest market, followed by Los Angeles, Hansen said. Census data do not provide statistics on height, but the Big Apple's demographics clearly favor Peter Manning.