Type: String
Identifies class or source of the BenchmarkSecurityID (699) value. Required if BenchmarkSecurityID is specified.
Same values as the SecurityIDSource (22) field
Added in protocol FIX.4.4
See in: FIX.5.0, FIX.5.0SP1, FIX.5.0SP2, FIX.5.0SP2 EP240.