London-based Arup Engineering is moving its regional office from Playa Vista to downtown Los Angeles after signing a 15-year, $57 million lease for 66,000 square feet at the Wilshire Grand office tower, located at 900 Wilshire Blvd.

The company said it plans to grow its local workforce to 400 employees in its downtown location, where it will take up three floors at Wilshire Grand.

Arup currently occupies about 38,000 square feet on Jefferson Boulevard in Playa Vista. The average asking rent in Playa Vista is $5.35 per square foot, compared with $3.51 per square foot downtown, according to Jones Lang LaSalle Inc.

Colliers International and New York-based Legacy Partners represented Arup in the lease negotiations. Cushman & Wakefield represented Hanjin/Korean Air, the owners and developers of the 73-story tower, the tallest U.S. building west of the Mississippi River.

The Wilshire Grand Building opened last year and cost around $1.4 billion to build.

Real estate reporter Ciaran McEvoy can be reached at [email protected] or (323) 556-8337.