SWIFT ISO 15022 - Code TOBK Financial acronyms The entire acronym collection of this site is now also available offline with this new app for iPhone and iPad. Meaning To Book: Certificate/title stays with the registrar/register and is booked in the shareholder account with the company. Usages Message type Field number Tag MT500 (Instruction to Register) 14 22F (Indicator) MT501 (Confirmation of Registration or Modification) 14 22F (Indicator) MT519 (Modification of Client Details) 13 22F (Indicator)