diff --git a/market/v1/msg.proto b/market/v1/msg.proto
index 3018143..8a40ee3 100644
--- a/market/v1/msg.proto
+++ b/market/v1/msg.proto
@@ -71,6 +71,7 @@ message MarketOrder {
   repeated string tags = 20;
   repeated string comment = 21;
   optional MarketOrder source = 22; // purchase is done via this field
+  optional uint64 maker_order_id = 23;
   // repeated string attachments = 14; // possible files included by
   // seller/buyer
 }