Boston-based private equity firm TA Associates has sold an eight-story, 89,000-square-foot office building at 898 N. Sepulveda Blvd in El Segundo for $35.5 million, according to broker Newmark Knight Frank.

The off-market transaction marks an 81 percent gain on their investment, which it purchased in 2011 for $19.6 million.

The buyer was a joint venture of Stanton Road Capital and Second City, which represented itself. NKF Capital Markets President Kevin Shannon, Executive Managing Director Ken White and Managing Director Michael Moore represented TA Associates in the sale.

The property, which is 98 percent leased, also contains a six-level parking structure. The building was constructed in 1979 and renovated in 2000. The buyer plans to make improvements to the property, stabilize the building at market rents and extend the parking garage’s master lease, Shannon said in a statement.

El Segundo, home to the corporate headquarters of Mattel and DIRECTV, “is a very strong office market that continues to see capital acquire and renovate older properties to attract tenants looking for creative space,” Shannon said.

Ciaran McEvoy can be reached at [email protected]