The disputed tax payments date back to a period from 2007 to 2009, a time when Messi helped to transform Barcelona into the world’s best team.
He has now, however, been fined £1.7m for three counts of tax fraud while his father has been given a £1.3m fine, although both men can appeal against these sentences at the supreme court.
Lionel Messi has always denied any knowledge of his tax affairs, saying he concentrated on football, while his father has claimed he left it all up to financial advisers.
The four-day hearing actually concluded in Barcelona on June 3, shortly before Lionel Messi left to join Argentina’s squad for the Copa America.
The 29-year-old forward joined the club’s academy in 2000, aged 13, and his family joined him in Spain soon after.
He made his competitive debut in 2004, at 17, and has now scored 453 goals in 531 appearances, winning five Ballon d’Or trophies for the world’s best player along the way.
With Barcelona, he has won eight league titles and four Champions League winner’s medals.
He is also Argentina’s leading goal-scorer but has found success on the world stage harder to come by, losing in four major finals, including last month’s Copa America.
Immediately after that defeat, he announced his retirement from international football.
Messi is not the only Barcelona star to come under scrutiny for his tax affairs, as team-mate Neymar was recently fined almost £40m by a Brazilian court for evading tax on his sponsorship deals.
Like Messi, he also denies any wrongdoing and is appealing against that ruling.