The ID source of ExDestination.
Valid values:
| 'B' | BIC (Bank Identification Code) (ISO 9362) |
| 'C' | Generally accepted market participant identifier (e.g. NASD mnemonic) |
| 'D' | Proprietary / Custom code |
| 'E' | ISO Country Code |
| 'G' | MIC (ISO 10383 - Market Identifier Code) |
Used in: