Identifies class of alternative SecurityID Valid values: 1 = CUSIP 2 = SEDOL 3 = QUIK 4 = ISIN number 5 = RIC code 6 = ISO Currency Code 7 = ISO Country Code 8 = Exchange Symbol 9 = Consolidated Tape Association (CTA) Symbol (SIAC CTS/CQS line format) 100+ are reserved for private security identifications