Co-working firms, led by WeWork Cos., have grown to meet the changing demands of the modern office and labor markets. Nowhere is it more evident than in gateway cities. In New York City, WeWork alone leases more than 1 percent of the city’s office space across 44 locations, according to Green Street Advisors. While the industry’s share of total office space is still small on a relative basis, its rapid growth is forcing investors to take notice.

In its 2016 report Shared workspaces: The market perspective, JLL pegged the co-working industry at only 0.7 percent of the total U.S. office market. It has grown since then to between 1 percent and 2 percent of the market, according to Jamie Russo, executive director of Global Workspace Association.

Co-working has shown up on investors’ radar, but not everyone is sold on leasing to the industry, with many wondering if it is a passing fad, or if eventually they will have to get on board.

When you look at the trends underpinning the growth of co-working space, the numbers are staggering. Freelancers currently make up 34 percent of the U.S. workforce, a number projected to grow to 43 percent by 2020, according to Intuit, the owner of TurboTax — and office portfolios will need to keep pace. By 2030, JLL predicts 30 percent of corporate real estate portfolios will be dedicated to co-working or flexible space solutions. The rise of the “gig economy” and companies’ changing employment needs are not the only trends fueling this shift toward a contractor-driven economy.

Co-working companies have stepped in to fulfill the square-footage needs of this growing segment of the workforce, and they have often made quite the premium to do so. According to the JLL report, shared offices cost about $139 per square foot, a 181 percent premium over the average class A central business district rental rate of $49.59 per square foot. When looking at average rental rates overall, that premium jumps to 331 percent, according to National Real Estate Investor.

Numbers like that will catch any investor’s eye.

Reg Clodfelter is a freelance writer based in Berkeley, Calif.