SWIFT ISO 15022 - Code SBLO Financial acronyms The entire acronym collection of this site is now also available offline with this new app for iPhone and iPad. Meaning Securities Blocked: Financial instruments are blocked due to a corporate action event, realignment, etc. 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)