The UnderlyingEvntGrp is a repeating subcomponent of the UnderlyingInstrument component used to specify straightforward events associated with the instrument. Examples include put and call dates for bonds and options; first exercise date for options; inventory and delivery dates for commodities; start, end and roll dates for swaps. Use UnderlyingComplexEvents for more advanced dates such as option, futures, commodities and equity swap observation and pricing events.