This message is used to instruct a broker on how to allocate executed shares to sub-accounts. It can also be used as a confirmation message through which third parties can communicate execution and settlement instructions between trading partners.

An Allocation message can be submitted with type "new", "cancel" or "replace". The AllocTransType (71) field indicates the purpose of the message. When submitting "replace" or "cancel", the RefAllocID (72) field is required. Replacement Allocation messages must contain all data for the replacement allocation.

The allocation record contains repeating fields for each order, sub-account and individual execution.

The total shares allocated must equal the Shares (53) value which must equal the total executed quantity of the original order. If present, the total shares in the execution section must also be equal to this value.

The number of sub-account instances is indicated in NoAllocs (78).

Multiple orders can be combined for allocation by identifying the number of orders in the NoOrders (73) field and each individual order in the OrderID (37) fields. Combined orders must have the same ticker, trade date, settlement date and side.