SWIFT ISO 15022 - Code SBLO 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)