SWIFT ISO 15022 - Code SSEX Financial acronyms The entire acronym collection of this site is now also available offline with this new app for iPhone and iPad. Meaning Sell Short Exempt: Order to sell short which is exempt from short-sale rules. Usages Message type Field number Tag MT502 (Order to Buy or Sell) 18 22a (Indicator) MT513 (Client Advice Of Execution) 35 22a (Indicator) MT576 (Statement of Open Orders) 43 22a (Indicator)