The 24-year-old was understood to have been available for that fee until July 31st, but the passing of that date means that his value will have increased substantially.
However, this has not deterred Spurs, who reportedly remain keen on the classy playmaker.
Malli scored an impressive 11 goals last season, while notching four assists, in Bundesliga action, which has alerted Mauricio Pochettino.
Although the Argentine is well-stocked in terms of attacking midfield options at White Hart Lane, Malli is believed to be a player he likes, which has not been effected by the increase of his price-tag.
The Mainz ace has been capped seven times by Turkey and was a part of their EURO 2016 set-up, albeit he only made it on to the pitch for 20 minutes in France.