SWIFT ISO 15022 - Code MR01 Financial acronyms The entire acronym collection of this site is now also available offline with this new app for iPhone and iPad. Meaning Mister Usages Message type Field number Tag MT500 (Instruction to Register) 40 22F (Indicator) MT501 (Confirmation of Registration or Modification) 40 22F (Indicator) MT519 (Modification of Client Details) 38 22F (Indicator)