American Realty Advisors has sold Waltham Corporate Center to Massachusetts General Physicians Organization for $116.7 million.

The physicians group is the largest tenant in the 295,000-square-foot complex, and extended its lease prior to the sale, according to a press release. The three-building complex is 94 percent occupied, according to American Realty Advisors, with National Grid the second-largest tenant.

A spokeswoman for Massachusetts General Physicians Organization did not return a message about the group’s plans for the property.

Glendale, California-based American Realty Advisors bought the three-building complex at 10, 40 and 52 Second Ave. for $106 million in 2007 from a joint venture of Rockwood Capital LLC and the Beal Cos.