SWIFT ISO 15022 - Code BLCA Meaning Blocked Corporate Action: Balance of financial instrument blocked following a corporate action, including proxy activities. Usages Message type Field number Tag MT508 (Intra-Position Advice) 35 93A (Balance) MT538 (Statement of Intra-Position Advices) 35 93A (Balance: Balance From) MT538 (Statement of Intra-Position Advices) 44 93A (Balance: Balance To)