I am trying to parse a FIX 4.4 AllocationInstruction (J) message, I want to identify whether an allocation is to be average priced. Unable to figure out which tag to use for that.

I’ve tried searching on https://fiximate.fixtrading.org/ and saw 2 tags AvgPxIndicator (field 819) and TrdType (field 828), none of these are part of FIX 4.4 AllocationInstruction.

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Another quote from the official FIX4.4 specification document, volume 5, page 37:

Post-Trade Allocation

Post trade allocations can be computed via one of two methods:

  1. Using Average Price: Each AllocAccount has a single AllocAvgPx (e.g. US and European) (see examples 1- 1, 2-1, 3-1)
  2. Using Executed Price: Combination of each AllocAccount and AllocPrice (unique LastPx) (e.g. Japan) (see examples 1-2, 2-2, 3-2)

But without asking your counterparty, this is just guesswork.

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