Porto have rejected a £22million bid from Wolves for their winger Jesus Corona.
The Portuguese side are holding out for £27m as that is the release clause in his contract.
Corona would be Nuno Espirito Santo's third signing from Porto this summer after signing Vitinha on Wednesday.
Having smashed their club transfer record to sign Fabio Silva on Saturday, the Wanderers have taken 20-year-old midfielder Vitinha on a season-long loan from the Portuguese club with an option to buy.
The Portugal Under-21 international was handed his debut for Porto last season and made eight appearances, including two alongside Silva, as the club won both the Primeira Liga and Taca de Portugal.
Porto also informed the Portuguese stock exchange they will pay Jorge Mendes' Gestifute agency £6.4m out of the £35m transfer fee they received from Wolves for Fabio Silva.
The Premier League outfit completed the mega-money move for the 18-year-old attacker last week, setting a new club record for a transfer fee in the process.
Now, according to a number of reports in Portugal on Thursday, it has emerged that some of that money will make its way to Mendes, even though he is not Silva's agent.
The 18-year-old is represented by the company Soccer Talents Vision (STV), who were alongside him when he put pen to paper on a five-year deal with Wolves.
Fosun International, the company that own Wolves, have previously said that Mendes is an advisor at the club.
Manager Nuno is represented by Mendes' Gestifute company, as well as a number of players. Rui Patricio, Joao Moutinho, Ruben Neves, Diogo Jota, Pedro Neto and Raul Jimenez are also signed to Gestifute.
Matt Doherty, the former Wolves right-back, also switched from his agent to Gestifute while at Wolves, according to The Times back in January.