Last price expressed in percent-of-par. Conditionally required for Fixed Income trades when LastPx (31) is expressed in Yield, Spread, Discount or any other type.
Usage: Execution Report and Allocation Report repeating executions block (from sellside).

Added in protocol FIX.4.4

See in: FIX.4.4, FIX.5.0, FIX.5.0SP1, FIX.5.0SP2.