SWIFT ISO 15022 - Code PWAL Financial acronyms The entire acronym collection of this site is now also available offline with this new app for iPhone and iPad. Meaning Period of Action: Open for acceptance until the next specified deadline in the announcement (if any). Usages Message type Field number Tag MT549 (Request for Statement/Status Advice) 16 25D (Status) MT564 (Corporate Action Notification) 51 22F (Indicator)