Release clauses in players' contracts have become part and parcel of professional football.
La Liga is where the stipulation is most common, whereby the likes of Barcelona, Real Madrid and Atletico Madrid are obliged to pre-determine a price they would be willing to sell at.
Should the fee be matched by an interested club, providing they meet specific requirements in the contract, talks may commence.
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Barcelona are particularly renowned for their use of release clauses, with Lionel Messi, Luis Suarez and Neymar all having signed deals that include extortionate fees.
And when I say extortionate, I mean they're absolutely ridiculous. In an investigation conducted by Squawka, the release clause of each and every Barcelona player has been revealed - here's the top 10.
10. PACO ALCACER - £86M
A £27 million summer signing from Valencia, Paco Alcacer ranks at number 10 with an £86 million release clause.
The highly-rated 23-year-old scored 13 La Liga goals last season but has yet to find the back of the net for Barcelona in four league appearances, three of which from the bench.
9. ANDRE GOMES - £86M
Another summer signing from Valencia, this time in a deal worth £41.7 million, Andre Gomes is a player for the future at Barcelona.
Following last month's 7-0 mauling of Celtic, manager Luis Enrique said of the Portuguese: "Andre is more of an offensive midfielder but he plays well, he's good, and has the physical conditions."
8. IVAN RAKITIC - £88M
Ivan Rakitic seamlessly adapted to life at Barcelona following his 2014 move with Sevilla and has since become a guaranteed starter alongside Andres Iniesta and Sergio Busquets.
His £88 million release clause is entirely justified given his contribution thus far.
7. JORDI ALBA - £132M
Blessed with scintillating pace, Jordi Alba has become indispensable at Barcelona because of his contributions in defence and going forward.
No one in their right mind would pay £132 million to sign him, though.
6. ANDRES INIESTA - £139.4M
Iniesta might be in the twilight years of his career, but he's still just as valuable to Barcelona as he was five years ago.
A wonderful attacking midfielder with quick feet, creativity and an eye for goal, the Spaniard has cemented his status as a club legend and will be sorely missed when he eventually leaves.
5. GERARD PIQUE - £143M
How Manchester United must regret selling Gerard Pique back to Barcelona for £5 million in 2008.
The Spaniard is now rated as one of Europe's best centre-backs, as suggested by his mammoth £143 million release clause at the Camp Nou.
4. SERGIO BUSQUETS - £172M
A stalwart of Barcelona's midfield, Busquets is the perfect defensive midfielder.
Strong and brilliant on the ball, the Spaniard is cherished in Catalonia and will likely stay there for the rest of his playing days - unless someone forks out £172 million.
3. LUIS SUAREZ - £172M
Luis Suarez has been nothing short of prolific since joining Barcelona in 2014, scoring 88 goals and assisting a further 43 in his first 100 appearances for the La Liga champions.
One of the best strikers to have ever graced La Liga, the 29-year-old is worth every penny of his £172 million release clause, let alone his £65 million transfer fee.
2. NEYMAR - £172M
Neymar's contract is slightly more complex than most of his Barcelona teammates.
The Brazilian signed a new deal this year that will see his £172 million release clause rise by £27 million each year until 2018, where it will peak at £215 million.
1. LIONEL MESSI - £215M
As Barcelona's prized asset, Lionel Messi was always going to possess the highest release clause.
The Argentine is arguably football's greatest ever player and a £215 million fee will see him stay in Catalonia for the foreseeable future.
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