Lionel Messi worth more than Cristiano Ronaldo- Study

Barcelona's Lionel Messi is the most valuable player in the world, well ahead of Real Madrid's Cristiano Ronaldo, according to a study by the International Centre for Sports Studies (CIES) Football Observatory.

The study used an algorithm based on 1,500 fee-paying club transfers since 2009 to determine that Messi's current transfer value is 220 million euros, while Ronaldo trails far behind at an estimated 133 million euros.

Messi, 27, has been increasingly linked with an exit from Barcelona, with both Manchester City and Chelsea reportedly interested in signing the four-time Ballon d'Or winner.

The Argentina captain endured a frustrating 2014 as Barcelona lost the Copa del Rey final and were beaten to the Liga title by Atletico Madrid, before Messi finished the World Cup with a runners-up medal after losing the final to Germany.

By contrast, Ronaldo, 29, lifted the Champions League trophy with Real Madrid and ended the year with over 60 goals in La Liga, with many observers backing him as the heavy favourite to lift the 2014 Ballon d'Or -- FIFA's top individual award which the Real Madrid forward will contest with Messi and Bayern Munich goalkeeper Manuel Neuer.

Chelsea have three representatives in the study's top 10, with Eden Hazard (99 million euros) third in the list, Diego Costa (84 million euros) fourth, and Francesc Fabregas (62 million) eighth.

Juventus midfielder Paul Pogba is reportedly worth 72 million euros after leaving Manchester United for nothing in 2012, while CIES believes Raheem Sterling would set Real Madrid back some 63 million euros should they decide to target the Liverpool forward.

There are six Premier League players in the top 10 overall, with Manchester City talisman Sergio Aguero (65 million euros) sixth and Arsenal star Alexis Sanchez (61 million euros) ninth.

Gareth Bale is valued at just 60 million euros by CIES after signing for Real Madrid for around 100 million euros in the summer of 2013, although Los Blancos have the most representatives in the top 100, with 11 players.

The variables included in CIES' econometric model refer to player performances (matches, goals, dribbles, etc.), their characteristics (age, position, contract duration, etc.), as well as competition level and results achieved by both their clubs and national teams.