One Shell Square, the tallest building in Louisiana, will be renamed to Hancock Whitney Center next year with the relocation of the bank from its longtime headquarters at 228 St. Charles Ave.

So long, One Shell Square. Hello, Hancock Whitney Center.

Next year, after more than a century in its current location, Whitney Bank is moving its operations from its longtime headquarters at 228 St. Charles Ave. to One Shell Square, Louisiana's tallest building, which will be renamed the Hancock Whitney Center.

The deal, nearly a year in the making, allows Whitney's Mississippi-based parent, Hancock Holding Co., the opportunity to sign a long-term lease in arguably the city's most iconic office tower and to hoist its name at the top.

"It's long enough that they've changed the name of the building," Whitney Bank's president, Joseph Exnicios, said Thursday of the lease for the Poydras Street tower. "This is a permanent move."

It will allow the bank and its roughly 400 employees to move about three blocks into more modern facilities than the early 20th-century building it now occupies, where bank officials say space has grown tight, forcing the bank to spread out into other nearby structures.

Whitney has signed a long-term lease with Hearst Investment Group, which purchased the 51-story building at 701 Poydras St. in 2015. Whitney will take over seven to nine floors.

The tower was designed by the renowned architectural firm of Skidmore, Owings and Merrill and built in 1972 for Shell Oil Co.

It was one of a series of high-rise buildings that energy companies commissioned along Poydras Street as Louisiana's fortunes soared on oil and gas, but it became one of the last remaining vestiges of that era: a high-profile office tower still bearing an energy company's name.

Shell — which will officially lose its name from the building it once owned — will continue to house more than 1,400 workers and contractors on 18 floors at the building.

The oil giant ultimately decided to shed unused space that was freed up in recent years as it streamlined operations. It also has trimmed staff as the energy industry has been hit hard by slumping commodity prices since 2014.

A Shell executive declined to say how much money it will save.

"We're more efficient in how we're using" the space, said Rick Tallant, asset manager for the Eastern Gulf of Mexico at Shell Deepwater. "It's a good deal for our shareholders and us to be able to reduce our operating costs."

Meanwhile, Whitney decided to relocate its local headquarters from a complex that's expanded to seven buildings.

The move is expected to be complete by the first half of 2018, according to John Hairston, president and CEO of Hancock Holding, which merged with Whitney in 2011.

Hairston, Exnicios and other bank executives discussed the bank's move Thursday ahead of the official announcement.

Sitting in the bank's boardroom, they explained the rationale for the move, balancing the bank's sense of history and their own nostalgia for its longtime home.

"The walls and the halls are thick with bank history, and really New Orleans history," Hairston said. "The facilities are precious to us." 

But the bank no longer needs a giant lobby to serve customers, and the seven-building complex doesn't fit its technological needs. 

Hariston declined to disclose the terms of Whitney's lease for its new home or how much the company expects to pay on construction costs.

It's unclear what will become of Whitney's existing buildings, in the heart of the Central Business District. Whitney was founded in 1883 a few blocks away on Gravier Street.

The bank executives have a general idea of what they'd like to happen with the buildings, but they declined to discuss them. They want to avoid being locked into one plan or a timeline, they said, only to say that the old building at 228 St. Charles will ultimately "be a symbol of New Orleans' emerging growth and economy."

They declined to speculate whether the bank would continue to own the properties, or if any subsequent use would have a nonprofit or commercial tilt.

"We're leaving ourselves open to consider those options," Hairston said. "We do have a preference, in terms of our participation here, but until we have a final answer, it's too early to say."

Hairston said the city's economy has diversified significantly since One Shell Square was built in the early 1970s and that having Hancock's name atop the building would be a symbol of that.

"We're certainly pleased to have the grand old banks highlighted in a grand old city, particularly when it's the 300th anniversary," he said, referencing the city's upcoming tricentennial.

Asked whether they expect the new name will catch on, Tallant cited the Sears Tower, the 108-story skyscraper in Chicago that's been officially known as the Willis Tower since 2009 but is still widely called by its old name.

"I think there's always a contingency of people in New Orleans that will know 701 Poydras as One Shell Square, but obviously the name on the building will be something different," he said.

Follow Richard Thompson on Twitter, @rthompsonMSY.