The success behind the Real Madrid finance is Florentino Pérez because all the time he made so many great decisions to make the team finance. This all credit goes to him, whether it's about bringing a big player or selling some of the team players. The real secret of the club's success is that you adopt that method which can improve the club state. Not like the president of Barcelona, who just spends big fee and big wages even if he gets banned later. Perez even said goodbye to Ronaldo when he demanded high wages. So it is true that Perez's transfer skill is outstanding, like he signs top players for zero fee, i.e. Kylian Mbappe.