Porto are insisting on €40 million to sell Danilo.
The Br azilian fullback is a top target for Real Madrid and Manchester United.
AS says Porto president Nuno Pinto da Costa is insisting on the price as Danilo's value was guaranteed as part of renegotiating a bank loan - an agreement which expires in September.
The €40 million demanded by Pinto da Costa would see €25 million go to the bank and the remainder to Porto.
Real regard the demands as excessive, particularly with Danilo inside the final 18 months of his current deal.