Manchester United and Manchester City will have to pay at least €50m (£37m, $54.8m) for Wolfsburg star Kevin de Bruyne, according to the Belgian's agent.
De Bruyne, who parted company with Chelsea in January 2014 after failing to win over manager Jose Mourinho, has gone on to become one of the best players in the Bundesliga.
His rise this season, which has seen him strike 14 goals and lay on 21 assists, has swiftly seen him linked with another move. Paris Saint-Germain and Bayern Munich have been credited with interest but reports suggest both Manchester clubs may consider offering him a route back to the Premier League.
However, the 23-year-old's agent, Patrick De Koster, has warned his client's suitors his valuation is rising all the time.
"Clubs are who are ready to bid €30m for Kevin have no sense of reality," he told Bild. "A player like Kevin has a market value of some €50m, €55m or even €60m by now."
While Wolfsburg are unlikely to catch league leaders Bayern, their seven-point advantage over third-placed Borussia Monchengladbach leaves them favourites to clinch Champions League football next season.
Also speaking to Bild, as translated by ESPN, Wolfsburg sporting director Klaus Allofs insisted De Bruyne is happy where he is but admits the club will have to "face up to" any significant offers at the end of the season.
"Kevin feels great here, and everything we told him would happen [when he signed] has happened," he said. "Something special has to come up for a player to want to leave us. Should that happen, we will face up to it."
De Bruyne, who spent just half a season as a Chelsea first-team player having previously spent time on loan in his native Belgium and Germany, was sold by the Stamford Bridge club for a fee of £16.7m in January 2014.