Synergy Investment & Development has purchased a 96,000-square-foot building in Boston’s Downtown Crossing district for $12.8 million.

Grubb & Ellis Co. represented Textile Building Trust in the sale of 99 Chauncy St.

Synergy also owns property on Congress Street, Broad Street and Tremont Street. Earlier this year, the firm sold a building on Summer Street for $11.5 million, according to previous reports in Banker & Tradesman.

"In its 66 years in Downtown Boston, 99 Chauncy St. has had a long history of sustained occupancy, making it an attractive investment for clients seeking long-term, stable cash flow," said Mike Edward, managing director and executive vice president of Grubb & Ellis in Boston. "Adding to its attractiveness, the property is located in an area with amenities to suit nearly everyone."

The 11-story building was approximately 90 percent occupied at the time of sale to multiple tenants, including the Department of Public Health and Miller Dyer Spears Inc. The property was originally constructed in 1935 and is within a few blocks of the MBTA’s Red, Orange and Green lines.

Synergy represented itself in the transaction.