SWIFT ISO 15022 - Code FIDE Financial acronyms The entire acronym collection of this site is now also available offline with this new app for iPhone and iPad. Meaning Confidential: Correspondence is to be confidential. 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)