One uCity Square, a $300 million life sciences building in University City, is now more than 90% leased less than six months after it opened in January.

Engineering and scientific consulting firm Exponent moved into 32,000 square feet earlier this month, taking up a full floor in the new building at 25 N. 38th St. after previously occupying 20,000 square feet at 3440 Market St.

Massachusetts-based Charles River Laboratories is also taking a half-floor at One uCity Square, which has a total of 400,000 square feet of space across 13 floors.

“It’s pretty incredible,” said Pete Cramer, vice president of development for Wexford Science & Technology, which developed the property in partnership with Ventas Inc. and the University City Science Center. “I think it’s a testament to the market. We started this building on spec without any leases. … Seeing that progression of velocity and leasing building after building is why we love this market.”

Cramer said the leasing pace is faster than it was at 3675 Market St., which opened in 2018 and is also part of the uCity Square campus.

Exponent, which is based in California, signed a 10-year lease at One uCity through 2033. The company currently has 70 consultants and plans to add about 10 to 15 positions each year until it reaches 100 employees in the new space, Philadelphia Office Director Ryan Siskey said.

Exponent spent the last 10 years at 3440 Market St., where its space included 4,000 square feet of labs. It will have 6,500 square feet of lab space at One uCity Square.

“We needed to move into space that was going to be more versatile and set up the service for another 10-year period,” Siskey said, adding that it was “extremely important” to be in University City because of its density of life sciences firms and proximity to local colleges.

Charles River Laboratories, helps pharmaceutical and biotechnology companies test drugs, is leasing 16,236 square feet in the building with plans to move in by the fall. While it has locations in Horsham, Malvern and Wayne, this is the company’s first space in Philadelphia.

Exponent and Charles River Laboratories join Century Therapeutics and Integral Molecular among One uCity Square tenants. There’s only a half-floor of life sciences and office space left to lease and about 12,000 square feet of retail available.

Wexford is working on another life sciences building at 38th and Market streets which is planned to have 225,000 square feet of space, multiple tenants, parking and more ground floor retail. Wexford is marketing the space to grocery stores, Cramer said, and hopes to break ground in the fall.