Northern Trust is moving its Florida headquarters to 600 Brickell and putting its current home across the street up for sale.

The bank will begin marketing its property at 700 Brickell and 710 Brickell for sale later this month, said Gavin Campbell, managing principal with Steelbridge, /the real estate broker representing the bank.

“From a market standpoint, it’s a good time to be selling and a good time to be leasing,” Campbell said. “We feel like we’re leasing low and selling high.”

Northern Trust is expected to relocate this fall and take close to three floors at 600 Brickell, plus a ground floor retail branch for a total of 62,000 square feet, making it the building’s largest tenant. The move allows the bank to modernize its headquarters, which have been located in the same location for more than 40 years, said John Fumagalli, Northern Trust’s Florida president. The bank built the 10-story building in the early 1970s.

“We were going to have to spend some significant money to modernize the facility,” Fumagalli said. “Given our growing footprint in Florida, we felt this was a better way to do it.’’ This gives us an opportunity to continue to grow and do it with a fresher and more contemporary feel.”

Steelbridge and CB Richard Ellis will be marketing the 67,000 square foot site, which runs the length of the entire block between Southeast 7th Street and Southeast 8th Street. Northern Trust last week demolished the colonial building at 710 Brickell that until last summer was occupied by Miami Today. A future buyer is expected to demolish the high-rise building and the adjacent parking garage. The site is zoned to allow over one million square feet, including any combination of high-density residential, office and hotel uses, Campbell said.

“With everything happening on Brickell, we’re expecting a high-level of interest in the site,” he said. “There are going to be a lot of options for what you can do there.”

A prime buyer for the Northern Trust property could be Swire Properties, whose massive Brickell CityCentre development is under construction just to the west of the site. The site would provide the key Brickell Avenue visibility and frontage the Swire project lacks.

Northern Trust’s signing gives 600 Brickell a key anchor tenant and brings the 40-story, 600,000-square-foot property to almost 40 percent leased, said Tracy Story, president of management and leasing for developer Foram Group.

“We believe that the quality of that tenant reinforces the quality of the building overall,” Story said.

The building, which recently became the only building of its kind in Florida to receive LEED Platinum certification, has signed leases with Boston Consulting Group, Hogan Lovells and The Ferraro Law Firm. These tenants will move in later this year and join existing tenants that include Credit Agricole bank, De La Peña Group and Doral Financial. Also coming this summer is Restaurant Du Cap by the owners of Zuma.