Warehouse condominiums in Waipio that went through foreclosure four years ago are being sold for what appears to be a tidy profit amid a strengthening and active industrial real estate market on Oahu.

San Diego-based investment firm Westcore Properties announced Tuesday that it has reached an agreement to sell 46 units at Waipio Business Center to a San Francisco-based investment firm for $21.9 million.

The sale will complete a plan by Westcore to snap up a struggling property after the economic downturn, improve operations and cash out.

"Our value-add strategy was accomplished, and it was time to move on," Don Ankeny, president and CEO of Westcore, said in a statement. "Industrial real estate vacancy rates on Oahu are among the lowest in the nation so we felt the market was in the right place for a strong sale."

WIC Partners LLC, a local partnership led by Samuel Chung, Serge Krivatsy and David Bierwert, developed Waipio Business Center in 2008 for an estimated $60 million with an aim to sell the project’s 99 units to warehouse users.

The complex was one of several that developers rushed to build on Oahu when Hawaii’s economy was hot and new warehouse space was in high demand.

A sharp downturn in the market at the end of 2008 caused financial difficulties for WIC, which had sold 27 of the 99 units that year for close to $22 million.

Lender GE Business Financial Services Inc. filed a foreclosure lawsuit in 2009 but the property failed to sell at auction in 2010 for more than the $20 million value of GE’s outstanding loan balance.

Westcore stepped in a year later to buy what had declined to 61 unsold warehouse condos in the project for $19.2 million. Over the past three years, the company sold 15 units to tenants at prices generally from $300,000 to $800,000 and raised occupancy from 20 percent to 84 percent.

The 46 remaining unsold units are being bought by Waipio Investments LLC, a company whose managing members are San Francisco-based firms Graymark Capital Inc. and Cornice Investments LP.

The pending sale follows two recent purchases of industrial land in Kapolei — a 123-acre parcel and a 54-acre parcel — by local developer Avalon Development Co. LLC and Chicago-based real estate investment firm Walton Street Capital LLC. Avalon and Walton intend to create industrial park subdivisions on the sites.

A report published in January by commercial real estate brokerage firm Colliers International said the vacancy rate for Oahu warehouse space declined last year to 2.7 percent from 3.8 percent the year before and represented a seven-year low just above a 2.3 percent vacancy rate in 2006.