So, what should we call the John Hancock Tower now?

The building formerly known as the Hancock Tower.Wiqan Ang for the Globe/File

You can still call it the John Hancock Tower, but the company that paid $930 million for New England’s tallest building can’t.

Now that John Hancock’s last lease in the office building has expired, owner Boston Properties Inc. can no longer use the financial services company’s name on the property.

“We’re not allowed to call it that any longer,” Boston Properties president Doug Linde said Thursday during an earnings conference call with analysts.

Hancock, which built the 62-story Back Bay tower nearly 40 years ago, opened its new headquarters in the Seaport District in 2004, the same year it was acquired by Manulife Financial Corp. The final lease ran out earlier this year.

The new name Boston Properties has dreamed up for the sleek glass tower? It’s 200 Clarendon, a nod to its street address. Meanwhile, the low-rise portion of the Hancock has been rebranded as 120 St. James as part of a bid to lure tech tenants.

Its not unheard of for iconic office buildings to change names.

Chicago’s Sears Tower has been called the Willis Tower since the British insurance company negotiated naming rights as part of a lease deal in 2009. That same year, Boston Properties renamed Citibank’s former headquarters in New York as 601 Lexington Ave. when the big bank moved out.

Sometimes, though, names outlive tenants. Manhattan’s Woolworth and Chrysler buildings were long ago vacated by their namesake companies, and the Back Bay’s Prudential Center retains that name because of a naming rights deal tied to its sale in 1998.

The most famous building in New England will no longer be called the Hancock Tower—at least by its owner.Wiqan Ang/The Boston Globe/File 2006

In the case of the Hancock Tower, the name was tied to John Hancock’s tenancy, said Justin Krebs, a former partner at Normandy Real Estate Partners, which owned the building before Boston Properties. When Hancock sold it, then-chief executive David D’Alessandro wrote into the contract that the name would stay put, Krebs said, but only if the company stayed within its walls.

“It had to have John Hancock occupancy to have that name,” Krebs said. “There was a trigger in the lease.”

John Hancock officials did not respond to messages seeking comment.

So what about the building that served as Hancock’s headquarters before the gleaming tower opened, the one with the beacon that changes color, depending on the weather?

It’s officially named the Berkeley Building, but everyone calls it the Old Hancock Tower. No problem — John Hancock owns it, having bought it back in 2006.