No longer used as of FIX 4.3. Included here for reference to prior versions.

*** REPLACED FIELD - See:

Appendix 6-F: 2.Replaced Fields: MaturityDay (tag 205) and UnderlyingMaturityDay (tag 314) [replaced in FIX 4.3] ***

Day of month used in conjunction with MaturityMonthYear (200) to specify the maturity date for SecurityType (167)=FUT or SecurityType (167)=OPT.