Insurance and retirement specialist Global Atlantic Financial Group will relocate 154 employees from Southborough to 20 Guest St., the former New Balance headquarters in Brighton.

The move scheduled to take place by year’s end increases the company’s office space from 30,000 square feet at 132 Turnpike Road to 46,290 square feet on the ninth and 10th floors of the 228,000-square-foot former New Balance building. Harvard Business Publishing previously filled 132,000 square feet at 20 Guest St. after New Balance relocated in September 2015 to its new 250,000-square-foot headquarters  at 100 Guest St. in the Boston Landing mixed-use development.

As part of the 1.8-million-square-foot Boston Landing project, New Balance’s development arm, NB Development Group, paid for construction of a new commuter rail station on the MBTA’s Framingham-Worcester line scheduled to open May 22.

“The train station was a big factor in their decision,” said Jim Halliday, managing director of NB Development Group. “It allows them to attract that urban labor market and it was a nice validation of the strategy for New Balance to build the station.”

Goldman Sachs founded Global Atlantic in 2004 and acquired Allmerica Life in 2005, renaming it Commonwealth Annuity and Life Insurance Co. It spun off Global Atlantic Financial Group as a separate company in 2013.

“This location presents a great opportunity for a modern space located closer to amenities and valuable access rail service, which we hope will provide more frequent service as the property is populated,” Global Atlantic said in a statement.

Transwestern Consulting Group’s Steve Purpura, Eric Smith, Tim Lahey and Perry Beal represented NB Development in the lease transaction. CBRE’s Rob Walles and Savills Studley’s Michael Mathias represented Global Atlantic.