SAN FRANCISCO-Shorenstein Co. is arranging about $150 million in mortgage financing on Hills Plaza, a mixed-use complex on San Francisco’s waterfront.

Several commercial banks including Chase Manhattan and Wells Fargo are said to be in the running for the assignment. FleetBoston Financial led the syndicated financing for Shorenstein’s July acquisition of Prudential Plaza in Chicago.

The San Francisco development firm is reportedly seeking a five-year, floating-rate mortgage with an “earn-out” provision that would permit it to increase the size of the loan as income from the property increases. Most of the complex’s office space is leased at about $30 persf, but new leases are being signed for $70 per sf to 90 per sf.

Hills Plaza is located at 345 Spear St., near the Embarcadero Center, with a view of the Bay Bridge, Treasure Island and Alcatraz. The complex includes two office buildings totaling 590,000 sf, 60,000 sf of retail space and garages, and a separately-owned residential development.

Office tenants include two law firms and the Gap, which is in the process of building a new corporate headquarters across the street. Shorenstein bought the property in 1994. Its current mortgage reportedly carries a balance of about $90 million.