Porto's president has admitted that he hopes striker Hulk will stay at the club.
The 25-year-old has an £83.5m buyout clause on his current contract, which runs to 2016.
Despite the eye-catching figure, Pinto da Costa is fearful that a club will one day be able to pay it.
"I hope that nobody meets Hulk's buyout clause, but I would not be surprised if someone pays it one day," he is quoted as saying in the Sunday Star.
Chelsea, Paris Saint-Germain and Barcelona have all been linked with a move for the Brazilian.