diff --git a/modules/purchase_trade/fee.py b/modules/purchase_trade/fee.py
index 89daccd..5d451e2 100755
--- a/modules/purchase_trade/fee.py
+++ b/modules/purchase_trade/fee.py
@@ -170,7 +170,7 @@ class Fee(ModelSQL,ModelView):
                 if lots:
                     return lots[0].lot_unit_line
         else:
-            return None
+            return self.unit
 
     def get_lots(self, name):
         logger.info("GET_LOTS_LINE:%s",self.line)