Oakland-based Citrine Advisors, a boutique real estate company whose previous projects have been in the Bay Area, has branched out to Portland with the acquisition of the historic Concord Building in the city's central business district.

As the tech sector grows in Portland, so does interest by investors such as Citrine, especially in acquiring vintage office buildings or other structures considered to have authenticity, which appeals to tech companies and their employees.

Built in 1891 and renovated in 1981 and 2016, the Concord Building includes six stories of creative office space and ground-floor retail, anchored by Mother’s Bistro & Bar. The property is at 204-210 SW Stark St. at the base of the Morrison Bridge.

San Francisco-based New Urban Properties, repped in the deal by CBRE Capital Markets' Charles Safley, sold the property to Citrine, which paid $5.3M. CBRE Capital Markets' Nick Santangelo secured the acquisition financing.

“Both the building and its location are a fit for our business model, which focuses on transforming vintage properties into high-quality environments,” Citrine President and co-founder Jerry Smith said.

The company has yet to detail specific plans for the building.

Citrine has experience with remaking historic properties. In Oakland, for instance, the company redeveloped the 1910 The Wagner, converting it to apartments in 2015 after a full renovation. Citrine sold the property last year for $10M.