diff --git a/modules/purchase_trade/valuation.py b/modules/purchase_trade/valuation.py
index 7c2cfde..6977301 100644
--- a/modules/purchase_trade/valuation.py
+++ b/modules/purchase_trade/valuation.py
@@ -138,11 +138,13 @@ class ValuationBase(ModelSQL):
         amount = round(price * qty * Decimal(sign), 4)
         base_amount = amount
         currency = sale_line.sale.currency.id if sale_line else line.purchase.currency.id
+        company_currency = sale_line.sale.company.currency if sale_line else line.purchase.company.currency
         rate = Decimal(1)
         if line.purchase.company.currency != currency:
             with Transaction().set_context(date=Date.today()):
-                base_amount = Currency.compute(currency,amount, line.purchase.company.currency)
-                rate = round(amount / base_amount,6)
+                base_amount = Currency.compute(currency,amount, company_currency)
+                if base_amount and amount:
+                    rate = round(amount / base_amount,6)
 
         values.update({
             'price': round(price, 4),