3) Marquinhos: Roma to PSG, £27m, 2013
The central defender had only joined AS Roma from Corinthians in the summer of 2012 for a fee of just £3.2m.
And yet just 12 months later the Brazil international was on his way to the Parc des Princes in a deal worth a whopping £27m, although it is safe to say that the 20-year-old’s switch to the French capital has not gone quite according to plan, with the youngster spending most of his debut campaign on the bench.