The Brazilian was linked with a Premier League move over the summer.
Corinthians have increased their asking price for in-demand striker Alexandre Pato according to deputy director of football, Eduardo Ferreira.
The 25-year old failed to convince at the Brazilian club following his move from Milan in 2013 and, after falling foul of the Corinthians fanbase, was sent on loan to rivals Sao Paulo in January 2014.
He has since gone on to impress - scoring 33 goals in 81 appearances so far – and has been linked to a return to Europe.
Spurs were amongst the most heavily-linked over the summer and are reportedly considering an approach in January – according to Goal.com - but now face a bigger financial outlay if they are to get their man.
Corinthians’ financial difficulties had meant they were previously willing to accept a fee of around £7.5 million but now want closer to £18.5 million, according to Ferreira.
"At the moment there are only enquiries. But if a club comes in with an offer of €25m (£18.5m), we will let him go, otherwise he will return [in January]," he said, in quotes published by Globo Esporte.
The signing of Pato represents a risk, given his woeful luck with injuries, but at £7.5 million he was probably worth a punt.
At £18.5 million however, his purchase would be ill-advised - to say the least - and Corinthians will have a hard time shifting him if they insist on such a figure.