Digital Realty Trust has bought its third major data center property in San Francisco for US$85m, the company said Wednesday. The multitenant facility at 360 Spear St. is 100% leased and is adjacent to another Digital-owned site at 365 Main St.

Pamela Garibaldi, VP of investor relations and corporate marketing at Digital, said while the real estate investment trust does not have any plans for new development in the city (currently starved for available data center capacity), it was potentially considering turning portions of its new property into colocation space once some of the ongoing leases there expire.

“We wouldn’t look to do any speculative development in San Francisco,” she said. “Value-add would be expanding our colo footprint and customer business into 360 Spear.”

In a major way, the 155,000 sq ft site is a good strategic fit for Digital because of its location next to 365 Main, a colocation facility the company bought from Rockwood Capital in 2010 along with four other US properties.

Digital has not made any definite plans to create additional colocation space at 360 Spear, but if it does, customers at 365 Main will be able to expand next door. Digital also owns another major San Francisco data center at 200 Paul Ave.

With its high electricity rates and real-estate costs, it is hard for San Francisco to compete with the neighboring Santa Clara in the Silicon Valley. Still, there is strong demand for colocation space in the city, Garibaldi said.

Another fully leased building bought in Atlanta

Digital announced another acquisition on Wednesday. In addition to the San Francisco property, the company bought a 344,000 sq ft data center in Atlanta from a major US airline the company did not name.

The building is adjacent to the Hartsfield-Jackson Atlanta International Airport.

As part of the deal, Digital signed a 10-year lease with the airline which will continue occupying about 170,000 sq ft of space at the data center. The rest of the facility is leased on a long-term basis to a provider of transaction-processing solutions to travel companies.