Can be used for SecurityType (167)=OPT to identify a particular security.

Valid values vary by SecurityExchange (207):

Exchanges: DTB (Frankfurt), HKSE (Hong Kong), and SOFFEX (Zurich)

0-9 = single digit "version" number assigned by exchange following capital adjustments (0=current, 1=prior, 2=prior to 1, etc).

Exchange: MONEP (Paris)

Use CFICode instead. See: Appendix 6-F: 7.Replaced values: OptAttribute (tag 206) with values in CFICode (tag 461) [replaced in FIX 4.3] ***