diff --git a/text_interface/addstock.py b/text_interface/addstock.py
index 213c75d..e463644 100644
--- a/text_interface/addstock.py
+++ b/text_interface/addstock.py
@@ -107,7 +107,7 @@ much money you're due in credits for the purchase when prompted.\n'''
             old_price = product.price
             old_hidden = product.hidden
             product.price = int(ceil(float(value) / (max(product.stock, 0) + self.products[product][0])))
-            product.stock += self.products[product][0]
+            product.stock = max(self.products[product][0], product.stock + self.products[product][0])
             product.hidden = False
             print "New stock for %s: %d" % (product.name, product.stock), \
                 ("- New price: " + str(product.price) if old_price != product.price else ""), \