Boatmen's Bancshares Inc. was one of the 30 largest bank holding companies in the United States when it was acquired by NationsBank in 1996.

The company, founded in St. Louis, Missouri, in 1847, claimed to be the oldest bank west of the Mississippi River at the time of its acquisition.

The bank was founded by George Knight Budd whose family had a fortune based in Philadelphia on the East Coast.

Its early history was marked by deadly citywide disasters in 1849 of a cholera outbreak that killed more than 1,000 and the Great St. Louis Fire of 1849 of May 17–18 that destroyed 23 steamers and at least 430 buildings.

Testifying against him was Joseph Charless, president of the Bank of Missouri, who had received for deposit water and mud-soaked notes from Thornton.