Putnam Investments has committed to relocating its headquarters from One Post Office Square to 100 Federal St. in Boston’s Financial District, signing a 15-year lease for 250,000 square feet occupying 11 floors in the 37-story tower beginning in 2018.

The move spans less than two blocks but could offer a world of difference in providing a vibrant environment for its 1,000 local employees. The 1.3-million-square-foot building is set to receive a proposed multimillion-dollar renovation and expansion project that would add shopping and dining options in the often-staid downtown neighborhood.

In November, majority owner Boston Properties submitted designs to city authorities for a two-story addition on the Congress Street side of the building including a winter garden and glass-enclosed atrium with food kiosks, bars and restaurants.

Putnam, which will share the building with other major tenants including Bank of America, will have a “highly visible presence in the lobby and on the building’s facade,” the $152 billion asset manager said in a press release.

“The location offers the ideal mix of modern, high-quality facilities in the heart of Boston’s financial district, with flexibility of space that will allow our firm to grow its onsite presence as our business grows over time,” CEO Robert Reynolds said in a statement.

Putnam will leave behind 240,000 square feet at One Post Office Square, where it has been headquartered since 1978. Spokesman Jon Goldstein said the company never considered locations outside Boston.

“As we did our due diligence, we feel like we found the optimal location to grow over time. Boston was our focus and we kicked a lot of tires in the process and looked at a lot of facilities, including our own (at One Post Office Square),” Goldstein said.

Putnam also occupies 330,000 square feet at 7 Shattuck Road in Andover and plans to expand its operations there, Goldstein said. That facility currently employs 900 people.

Putnam’s decision is expected to have a ripple effect upon other large office tenants contemplating moves in the downtown area over the next few years.

Santander Bank is looking for approximately 300,000 square feet of office space as soon as 2017 as it looks to consolidate its local offices in a single location, according to a real estate source. The bank has offices at 28 State St. for its Santander Global Advisors investment arm and regional offices at 75 State St.

And Wells Fargo will leave behind offices at 1 Boston Place, 101 Federal St. and 200 Berkeley St. after leasing 125,000 square feet at 125 High St. and relocating 775 employees there over a three-year period beginning late this year.