For Fixed Income: Amorization Factor for deriving Current face from Original face for ABS or MBS securities, note the fraction may be greater than, equal to or less than . In TIPS securities this is the Inflation index.
Qty * Factor * Price = Gross Trade Amount
For Derivatives: Contract Value Factor by which price must be adjusted to determine the true nominal value of one futures/options contract.
(Qty * Price) * Factor = Nominal Value
(Note tag # was reserved in FIX 4.1, added in FIX 4.3)