Flexible space is heavily concentrated in Philadelphia's Market West submarket, which accounts for 47.5% of the market's flexible space inventory.

In the City of Pittsburgh, new inventory of office-flex space has come to market of late. The report on the Pittsburgh office-flex market notes that Pittsburgh's flexible office space inventory grew to 616,000 square feet by the end of the second quarter of this year, an increase of 121,000 square feet or approximately 24%, from a year earlier. The office-flex market has grown by more than 250% since 2014, according to the report.

Flexible space currently accounts for 0.8% of Pittsburgh's total office inventory, up from 0.6 %a year ago.

"Pittsburgh's universities and growing technology industry have helped accelerate the demand for flexible office space," says Jeffrey Ackerman, managing director, CBRE. "Currently, there are 18 different flexible office space operators in Pittsburgh offering lease term flexibility and highly appealing workplace environments."

Flexible space is heavily concentrated in Pittsburgh's Downtown submarket, which accounts for 34.4% of the market's flexible space inventory.

National Office-Flex Market Trends

Nationally, the flexible office space sector currently occupies a cumulative 71 million square feet, or 1.8% of the office space in 40 U.S. markets.

CBRE forecasts the national flexible office space will expand to approximately 13% of office space by 2030, reaching up to 600 million square feet. Even in a low-growth scenario, CBRE sees flexible office space claiming up to 6.5% of the market by 2030.

Fueling that growth is demand from small businesses and enterprise users alike that favor the flexibility of office accommodations on relatively short-term leases, allowing them to expand or contract their space according to the needs of their business. Additionally, the flexible office space category has room to grow in every U.S. market, CBRE states. Even markets where flexible office space is well established—such as San Francisco at 4% of its office market and Manhattan at 3.6%—aren't as penetrated as major international markets like London and Shanghai, both at 6%.

"We're seeing a fundamental change in the expectations that organizations and their employees have for the workplace. This change is spurring an increasing number of companies to engage with flexible office solutions that provide the physical environment and business terms they prefer. This shift is ongoing," says Julie Whelan, CBRE's Americas head of occupier research. "There are some very bold predictions in the marketplace – with some calling for flexible space accounting for as much as 30% of office space in the future. There is simply not enough available office space to support this supply without even more drastic changes in tenant behavior."