The Spanish side have announced the 21-year-old, who had been targeted by Manchester City, will stay at the club until 2017, with his buy-out clause rising to €45m
Athletic confirmed the 21-year-old Spain international – whose previous deal expired in June 2015 – has added a further two years to his current terms, with his buy-out clause rising from €37.5 million to €45 million.
The club wrote on their official website: “Athletic Club and the player Iker Muniain have signed the renewal agreement whereby the player will remain with the Reds and Whites until June 30 2017 and his termination clause will rise from €37.5 million to €45 million.”
Goal reported in April that Manchester City were considering a £15 million move for Muniain.
The midfielder - who scored seven goals and made three assists in 35 league appearances for Athletic last term - has come through the ranks at the Basque club and has one Spain cap to this name.