When it comes to SunTrust Bank, Atlanta's loss is Cousins Properties' gain.

The Atlanta-based commercial real estate firm secured the headquarters for the soon-to-be-merged SunTrust and BB&T Corp. in Charlotte. The bank, expected to be renamed Truist, inked a 15-year deal for 561K SF at Hearst Tower, a 47-story, 970K SF tower in Uptown Charlotte.

The deal comes four months after SunTrust and BB&T announced their plan to merge and establish a new headquarters in Charlotte. The $66B merger means Atlanta is not only losing a corporate headquarters, but also a hometown bank that grew with the city to become the sixth-largest in the U.S. SunTrust is the largest bank in Georgia by deposits.

SunTrust and BB&T executives have described the pending merger, an all-stock transaction, as one of equals, creating Truist, which will tally more than $400B in assets, $300B in loans and $324B in deposits with more than 10 million households in the U.S.

For Cousins, the deal could be a boon to its balance sheet, as the bank has the option to buy Hearst Tower from the developer for $455.5M by the end of 2019, Cousins officials said in a release. To facilitate the move, Bank of America and a host of unidentified tenants have agreed to move out to accommodate Truist.

"BB&T and SunTrust's decision further validates Cousins' strategy to own trophy office towers in the best urban submarkets throughout the Sun Belt," Cousins CEO Colin Connolly said in a release.