FIX Error: Missing OrderQty (38) – Explained
Tag 38 (OrderQty) specifies the total quantity of shares, contracts, or units to be traded. This field is mandatory for NewOrderSingle (35=D) and OrderCancelReplaceRequest (35=G) messages.
Root Cause
1) Quantity not captured from order entry, 2) Message builder omits OrderQty, 3) Quantity validation fails leaving field empty, 4) Zero quantity filtered out incorrectly.
Broker/Exchange Action
Broker rejects with RefTagID=38, SessionRejectReason=6. Order is not accepted.
Client/Your Action
1) Ensure OrderQty is captured and validated, 2) Set OrderQty to positive integer, 3) Check quantity is within broker limits, 4) Verify field is not filtered out.
Example FIX Message
How FIX Doctor Detects This
FIX Doctor checks NewOrderSingle and OrderCancelReplaceRequest messages for tag 38. Missing OrderQty triggers an error.
Related Errors
Analyze Your FIX Logs
Upload or paste your FIX logs to automatically detect this error and get detailed diagnostics.
Analyze FIX Logs