FIX 4.0 : Sequence Reset <4> message

Structure | Sample Message | Related Messages


The Sequence Reset <4> message is used by the sending application to reset the incoming sequence number on the opposing side. The Sequence Reset <4> message can be used in the following situations:

  • During normal resend processing, the sending application may choose not to send a message (e.g. an aged order), the Sequence Reset <4> can be used to mark the place of that message.
  • During normal resend processing a number of administrative messages are not resent, the Sequence Reset <4> message is used to fill the sequence gap created.
  • In the event of an application failure it may be necessary to force synchronization of sequence numbers on the sending and receiving sides

The sending application will initiate the sequence reset. The message is used to reset the value of the next sequence number to be transmitted.

If the GapFill field is not present (or set to N), it can be assumed that the purpose of the Sequence Reset <4> message is to recover from an out-of-sequence condition, therefore, the MsgSeqNum <34> in the header should be ignored (i.e. the receipt of a Sequence Reset <4> message with an out of sequence MsgSeqNum <34> should not generate resend requests).

If the Gap Fill field is present (and equal to Y), the MsgSeqNum <34> should conform to standard message sequencing rules.

The sequence reset can only increase the sequence number; if a sequence reset is received attempting to decrease the next expected sequence number the message should be rejected and treated as a serious error.


Tag Field Name Req'd Comments
<MessageHeader> Y MsgType <35> = 4
123 GapFillFlag N
36 NewSeqNo Y
<MessageTrailer> Y


Sample Message

The '^' character is used to represent SOH character.


Related Messages