Swansea have put a £50million price tag on Gylfi Sigurdsson.
The move comes as the Icelandic playmaker continues to be heavily linked with Everton and Leicester.
Swansea remain determined to keep hold of Sigurdsson, who was named the club's player of the year for the second successive campaign last season.
The 27-year-old scored nine league goals and had 13 assists in a team which spent the entire season battling against relegation.
It was understood Swansea wanted at least £40million if they were to sell Sigurdsson, but that figure has now been revised with transfer fees spiralling this summer.