Kylian Mbappe named world’s most valuable player with transfer price tag of US$219.5m

• The CIES Football Observatory uses such indicators as player age, performance, career progression and contract duration to arrive at a transfer value
• The top five was rounded off by Barca youngster Pedri at US$144.4m and Borussia Dortmund’s English midfielder Jude Bellingham at US$142.9m