SWIFT ISO 15022 - Code BLOC Financial acronyms The entire acronym collection of this site is now also available offline with this new app for iPhone and iPad. Meaning Account Blocked: Your account is blocked, no instruction can settle over the account. Usages Message type Field number Tag MT537 (Statement of Pending Transactions) 19 24B (Reason) MT537 (Statement of Pending Transactions) 65 24B (Reason) MT548 (Settlement Status and Processing Advice) 12 24B (Reason) MT549 (Request for Statement/Status Advice) 17 24B (Reason)