SWIFT ISO 15022 - Code BLCA Financial acronyms The entire acronym collection of this site is now also available offline with this new app for iPhone and iPad. 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)