SWIFT ISO 15022 - Code NOPRINC Meaning Notional Principal Contracts Usages Message type Field number Tag MT574.W8BENO (IRS 1441 NRA-Form W8-BEN) 25 16R (Start of Block) MT574.W8BENO (IRS 1441 NRA-Form W8-BEN) 27 16S (End of Block)