Sources told press agency AFP that Pique has been ordered to pay €2.1m (£1.9m, $2.36m) after he was convicted of image rights fraud.
In May, the high court reportedly rejected the defender’s appeal against a 2016 ruling which found he had handed over his image rights to a company he owned called Kerad Project purely to gain a tax advantage.
This enabled him to pay a corporate tax rate of 30%, rather than a personal income tax rate of 45% between 2008 and 2010.
As a result, he has been ordered to pay €1.5m in tax arrears and a €600,000 fine.
He can, however, appeal to Spain’s supreme court.
Portuguese football manager Jose Mourinho, Manchester United striker Alexis Sanchez and ex-Liverpool and Real Madrid midfielder Xabi Alonso have also been under the cosh.
In a further twist, Pique’s wife, Colombian singer Shakira, is facing scrutiny over whether she was actually resident in Spain, rather than the Bahamas as she claims.
This could see her hit with €14.5m in back taxes plus fines.