The CIES Football Observatory labeled Kylian Mbappe's move to Paris Saint-Germain as the worst of all deals that took place this summer. The research institute based in Switzerland analyzed a series of transfers by taking into account the ratio of players' prices and quality, with the French vice-champions being generally recognized as the worst-performing club in the player market.
Mbappe's deal value will increase to 180 million euros next summer, although the CIES algorithm values the young talent at only 92.6 million euros.
Meanwhile, Liverpool's addition of Mohamed Salah is considered the best purchase. Although 50 million euros were paid for the leader from Roma, according to the study, his value is almost 70 million.
Other clubs that have considerably overpaid are Barcelona and Manchester City. There is a good chance that Barcelona will ultimately pay 147 million euros for Ousmane Dembele, but according to CIES, this is an overpayment of 51.2 million. On the other hand, Manchester City broke the record with 57.5 million euros spent on defender Benjamin Mendy, who is valued at only 28.5 million. Furthermore, Manchester City released Nolito, valued at 27.4 million, for just 10 million.
The latter transfer is ranked second on the list of best deals, with another player leaving Roma, Antonio Rudiger, taking the third spot. This defender, valued at 54.2 million euros, joined London's Chelsea for 39 million.
