#1 Neymar Jr. - FC Barcelona to Paris Saint-Germain

Not much of a surprise then, is it?
It's a testament to how incredible this transfer was that Neymar's move to Barcelona from Santos was already the 5th most profitable transfer of all time. To then earn the most profit ever on top of that required an incredible amount.
€222,000,000 was that incredible amount, and Paris Saint-Germain received one of the best footballers in the world for that price. Barcelona have used the money from the deal to bring in Ousmane Dembele and Philippe Coutinho, and by Lionel Messi's own admission, are better off:
"Without Neymar, we are more balanced," Messi told World Soccer. His departure meant a change in our way of playing, we lost a lot of attacking potential, but it helped in the defensive sense. We are currently very well armed in the midfield; this makes us stronger in defence."
It was viewed as a disaster for Barcelona at the time, but looking back with perspective, perhaps the Blaugrana were better off. They certainly profited monetarily.
Fee Paid: €88.2m
Fee Sold: €222m
Profit: €133.8m