A growing South Shore developer has claimed its stake in the Boston office market with a $43.5M purchase of a Financial District building.

FoxRock bought the 77K SF 176 Federal St. from a holding company controlled by Samer Khanachet, the chief operating officer of Kuwait Projects Co., according to Suffolk County land records.

The 121-year-old building is 80% occupied and tenants include law firm Rich May and investment banking company Capstone Partners, according to a FoxRock spokesperson.

“We’re hard at work building a flexible leasing solution that offers our tenants bespoke leasing options that suit their business’ specific needs,” FoxRock Director of Business Development Bryan Giudicelli said in a statement. “This property will play a key role in that new leasing model, which we will be launching in the coming months.”

The building sits less than a five-minute walk from South Station, features a three-story atrium and views of the Rose Kennedy Greenway and Boston Harbor. FoxRock recently paid $33M for a 159K SF office in Burlington, and its portfolio spans more than 4M SF across multiple asset classes, according to the developer.

FoxRock’s purchase is a sizable acquisition in the district beset by some of the worst fundamentals across the Greater Boston office market. The Financial District had Class-A vacancy of 11.9% in Q3, according to Hunneman research. The Financial District has accounted for 1.5M SF of negative absorption in the past 12 months in the Boston market only recently showing signs of recovery.