Bilbao has a tradition of signing Basque players, and once they sign them they don’t sell their players for ease. You can ask Bayern Munich and Manchester United for confirmation.
To combat this the club over several years have worked in big buyout clauses to contracts which protect them to a certain extent but they found out with Javi Martinez that sometimes clubs will pay whatever it takes and now some players are resistant to huge clauses in their contracts, because they know they’ll want to move if a huge offer comes in.
Nineteen year old centre back Aymeric Laporte has also had his buyout clause increased to €36m and been given a big pay rise, because Arsenal and other clubs made contact over signing the young player.
Marca report on Saturday that Athletic Bilbao were deeply concerned by the approaches and decided to throw a load of money at Laporte and get him to commit to a bigger buyout fee.
Bilbao know very well that if the player fulfills his potential it wll be very difficult to stop the transfer from happening but Bilbao club feel it gives them a lot more protection, and would mean a bigger transfer fee should he leave the club.
The renewal was a surprise for everyone and it might concern the interest from the bigger clubs in January but as for now Arsenal are still in the game and he is a talent for Arsenal to look for the future.