Bucking Boston’s biggest real estate trend, John Hancock Financial Services is closing shop in the Seaport.

The insurance company is returning its headquarters to Back Bay, where it already has a 1.2M SF campus and employs over 2,000. Its 465K SF Seaport headquarters at 601 Congress St. employs 1,100 people, all of whom will be transferred by the end of 2018 to two Back Bay buildings at 200 Berkeley St. and 197 Clarendon St., the Boston Business Journal reports.

The Seaport complex has been the company’s headquarters since 2004, when it was acquired by Toronto-based Manulife Financial. Manulife owns the Seaport building and is its only tenant. It is currently evaluating whether to lease or sell the property, company spokesperson Anne McNally told the BBJ.

The move to leave the neighborhood comes as many companies are looking to find a way in. Reebok and General Electric have opened headquarters in the neighborhood. Amazon could add as many as 4,000 non-HQ2 jobs in a nearby office complex, which some argue shows the company favors the area over a city-preferred site for HQ2 in East Boston.

The move is a significant change under new John Hancock CEO Marianne Harrison, who was promoted to the position last fall and is the first female chief executive in company history.

Harrison sent a memo to Hancock employees Tuesday, saying the company had enough space in Back Bay, given the number of local employees and how many work remotely. Along with the weather beacon-capped 200 Berkeley and 197 Clarendon, Hancock has approval to build a third office tower in Back Bay. The 26-story, 388-foot tower at 380 Stuart St. could be developed for Hancock or another tenant, according to McNally.

Back Bay’s — and Boston’s — tallest tower, the nearby 200 Clarendon, was closely tied to the company until 2015 when its lease and “John Hancock Tower” naming rights for the building expired.

The company’s latest real estate move is not expected to entail a reduced headcount. Harrison informed employees in her memo the move from the Seaport to Back Bay would begin this summer.