The NewOrderList(35=E) message may be used in one of two ways depending on which market conventions are being followed.
In the "Non disclosed" convention the NewOrderList(35=E) message is sent after the bidding process has been completed, by telephone or electronically. The NewOrderList(35=E) message enumerates the stocks, quantities, direction for the trade and may contain pre-allocation information.
In the "Disclosed" convention the NewOrderList(35=E) message is sent before the bidding process is started, by telephone or electronically. The NewOrderList(35=E) message enumerates the stocks and quantities from the bidding process, and may contain pre-allocation information. The direction of the trade is disclosed after the bidding process is completed.
Additional detail from the official source
This message may also be used as the first message in the transmission of a program trade where the bidding process has been done by means other than FIX. In this scenario the messages may either be used as a staging process, in which case the recipient (e.g. broker) will start execution once either a ListExecute(35=L) message is received or for immediate execution, in which case the orders will be executed on receipt.
Where multiple waves of a program trade are submitted as a series of separate lists to the receiving party, ClOrdLinkID(583) may be used to link the orders together.
Message structure 2824 distinct fields
Source order, including nested components and groups. Group counts precede the repeated entries. “Required here” is relative to the enclosing component or group, not unconditional in the message. A dash means not marked required; conditional requirements remain in the source notes. This is a reference, not a counterparty-specific validator.
Includes nested components and groups. Escape clears the filter.