Rudolf Elmer (born 1 November 1955) is a Swiss private banker, whistleblower, and activist.
He worked as a banker at Julius Bär from the 1980s to his dismissal in 2002.
At the time of his leaving, he was head of the bank's Caribbean operations for eight years.
After initial, unsuccessful attempts to disclose client information in 2005, he was arrested by Zürich authorities and held for 30 days.
In 2008, Elmer illegally disclosed confidential bank documents to WikiLeaks detailing the activities of Julius Bär in the Cayman Islands and its role in alleged tax evasion.
In January 2011, he was convicted in Switzerland of breaching secrecy laws and other offenses.
He was rearrested immediately thereafter for having again distributed illegally obtained data to WikiLeaks.
Julius Bär as well as select Swiss and German newspapers alleges that Elmer has doctored evidence to suggest the bank engaged in tax evasion.