U.S. Senator Phil Gramm plans to join the investment bank UBS Warburg as a vice chairman after his current term ends in January.

Mr. Gramm, a Democrat turned Republican from the U.S. state of Texas is retiring after 24 years in Congress. Mr. Gramm says he will advise UBS Warburg on political matters and will work with corporate clients to help them grow and create jobs.

Mr. Gramm was the chief author of the 1999 Gramm-Leach-Bliley law, which lifted Depression-era rules that separated banking from the securities business.