SWIFT ISO 15022 - Code GAIN Financial acronyms The entire acronym collection of this site is now also available offline with this new app for iPhone and iPad. Meaning Gain/Amount Received Usages Message type Field number Tag MT307 (Advice/Instruction of a Third Party FX Deal) 34 22H (Indicator: Gain/Loss Indicator) MT307 (Advice/Instruction of a Third Party FX Deal) 38 22H (Indicator: Gain/Loss Indicator)