It would cost a team a lot of money to acquire Leo. Getty Images With the transfer window now open in many of the world's top soccer leagues, the CIES Football Observatory has released its semi-annual list of the most valuable football players in the world.

Lionel Messi of Barcelona in Spain's La Liga tops the list with a staggering transfer value of $262 million (€220 million), and nobody else is even close.

And that would just be the estimated cost of acquiring the rights to the Argentine footballer. If a team were able to persuade Barcelona to sell Messi, the new club would then have to negotiate a new contract with the player.

Messi reportedly makes slightly more than $50 million per year with his contract at Barça.

There are a lot of valuable athletes in North America, and while this side of the Atlantic uses a different means of transferring players between teams, it is hard to imagine any team would pay $262 million for a player's rights and then give pay that player a $50 million annual salary.

Messi's transfer value is calculated by examining transfer fees since 2009 and variables such as recent performance, age, position, current contract, and team performance.

For many of the world's top association football leagues, January marks the midseason transfer window in which clubs are given approximately one month to add players from international leagues.

Here is the rest of the top 10:

Lionel Messi, Barcelona (Spain) — $262 million (€220 million) Cristiano Ronaldo, Real Madrid (Spain) — $158 million (€133 million) Eden Hazard, Chelsea (England) — $118 million (€99 million) Diego Costa, Chelsea (England) — $100 million (€84 million) Paul Pogba, Juventus (Italy) — $86 million (€72 million) Sergio Agüero, Manchester City (England) — $77 million (€65 million) Raheem Sterling, Liverpool (England) — $75 million (€63 million) Francesc Fàbregas, Chelsea (England) — $74 million (€62 million) Alexis Sánchez, Arsenal (England) — $73 million (€61 million) Gareth Bale, Real Madrid (Spain) — $71 million (€60 million)