Image courtesy of Skidmore, Owings & Merrill

The Boston Redevelopment Authority has approved a 26-story office tower which will be developed and occupied by John Hancock Life Insurance Co. at 380 Stuart St. in Back Bay.

John Hancock, the U.S. arm of Toronto-based Manulife Financial Corp., proposed a 625,000-square-foot tower in September to replace the existing nine-story office building that it owns at 380 Stuart St.

Designed by architects Skidmore, Owings & Merrill, the new tower is touted by developers as a “bold design” that will improve the Back Bay streetscape with a pedestrian pathway lined with cafes and amenities. The crown atop the 390-foot-tall structure – which has drawn comparisons to an office paper shredder – would contain office space, conference center, roof deck and penthouse for utility storage.

The building’s curved facade, large entry canopy and covered pedestrian areas will reduce wind impacts on the surrounding neighborhood, according to a study by consulting engineers Rowan Williams Davies & Irwin Inc.

Hancock will self-finance the $350-million project, an executive told the Boston Globe. Colliers International is the development advisor.

Hancock sold its iconic 62-story Hancock Tower at 200 Clarendon St., New England’s tallest building, to Beacon Capital Partners in 2003.

The building was renamed 200 Clarendon this summer by the current owner, Boston Properties, after Hancock’s naming rights expired. Hancock no longer has any office space in the building. Hancock’s U.S. headquarters will remain at 601 Congress St. in the Seaport District.