Transaction Begin Message Fields (Options Only)

The Transaction Begin message indicates any subsequent messages, up to the accompanying Transaction End message, are all part of the same transaction block. All PITCH messages corresponding to such an event would be included between a Transaction Begin message and Transaction End message. It is important to note that transaction blocks are currently used in US Options for symbol state transitions only, but may be expanded to other use cases with notice. Transaction Begin messages do not alter the book and can be ignored if messages are being used solely to build a book.

Feed processors can use a transaction block as a trigger to postpone publishing a quote update until the end of the transaction block.