diff --git a/addons/stock_account/models/stock.py b/addons/stock_account/models/stock.py
index 01278afee97..156ee0dedab 100644
--- a/addons/stock_account/models/stock.py
+++ b/addons/stock_account/models/stock.py
@@ -303,7 +303,7 @@ class StockMove(models.Model):
         if qty_to_take_on_candidates == 0:
             move.write({
                 'value': -tmp_value if not quantity else move.value or -tmp_value,  # outgoing move are valued negatively
-                'price_unit': -tmp_value / move.product_qty,
+                'price_unit': -tmp_value / (move.product_qty or quantity),
             })
         elif qty_to_take_on_candidates > 0:
             last_fifo_price = new_standard_price or move.product_id.standard_price