The state Office of Hawaiian Affairs has bought a historic Iwilei office complex as part of an investment strategy and long-term plan to move out of office space the agency rents for close to $1 million a year.

OHA purchased Gentry Pacific Design Center, a 185,787-square-foot building on about four acres at 560 N. Nimitz Hwy. between City Mill and Kmart.

The sale closed Monday for about $21 million, according to property records.

The seller was an affiliate of local real estate development firm Gentry-Pacific Ltd.

OHA, which has about 150 employees, leases roughly 30,000 square feet of office space in Pacific Park Plaza at 711 Kapiolani Blvd.

Tenants at the Design Center won’t be affected by the sale under terms of their leases. OHA said it plans to move its offices to the Design Center as space becomes available, though the agency has no timetable for moving.