CGI-MP (sometimes shortened to "CGI") is a multi-bank usage profile maintained by the Common Global Implementation Initiative — a working group of corporate-banking platforms, treasury vendors, and major correspondent banks. The profile pins a common subset of ISO 20022 corporate-payment messages so a single integration can fan out to multiple banks.
CGI-MP v3 is the current version. It pins pain.001.001.09 for credit transfers, pain.008.001.08 for direct debits, camt.053.001.08 for statements, camt.054.001.08 for notifications, and pain.002.001.10 for status reports.
The practical value: a corporate treasury that submits its outbound files in CGI-MP v3 shape can usually run the same XML at half-a-dozen tier-1 banks with only the GroupHdr InitgPty and the channel-specific wrapper changing. The per-bank rule-pack differences (which iso-compliant catalogs) typically live in the *overlays* on top of CGI-MP — bank-specific NbOfTxs/CtrlSum rules, batch-booking flags, specific extensions in <SplmtryData>.