The RSA–Trustmark Building, originally the First National Bank Building, is a 34 story, 424ft International Style office tower located in downtown Mobile, Alabama. Most recently known as the AmSouth Bank Building, it had been named in honor of its largest tenant until 2006, AmSouth Bancorporation. It was renamed the GM Building by its new owner, Retirement Systems of Alabama, in 2009. Following a lease agreement with BancTrust Financial Group and its community bank subsidiary, BankTrust, it was renamed again. BancTrust Financial Group was purchased in 2013 by Trustmark Corporation, a Mississippi based financial institution. The building officially became the RSA–Trustmark Building. Trustmark occupies of the tower, including the lobby floor and floors 25 through 31.HistoryBoth the original First National Bank building and the three-story Neo-Renaissance style U.S. Customs House were demolished in 1963 to clear the site for the new building. The office tower was completed in 1965 and was the tallest building in Alabama from that time until 1986, when it was surpassed by the Wachovia Tower in Birmingham. It remained the tallest building in Mobile until the completion of the RSA Battle House Tower in 2007. It was temporarily the 2nd-tallest building in Mobile and the 4th-tallest building in Alabama for roughly a year until renovation of the Renaissance Hotel was completed in 2008 with the addition of a spire, which rose that building's height to 536 feet from its previous height of 277 feet .
