Spain’s tax agency has asked El Mundo to hand over leaked documents that the newspaper reported purport to reveal the offshore holdings of some of the country’s biggest soccer stars. El Mundo has been running stories that report on allegations that some people in the soccer world, including Real Madrid’s star forward Cristiano Ronaldo, have improperly benefited from having image rights income paid into offshore accounts established by Portuguese soccer entrepreneur Jorge Mendes’s Gestifute agency. Based on documents passed to a handful of European media organisations from individuals behind a website called Football Leaks, the stories have sparked the interest of Spain’s tax authorities. The group stopped publishing documents on its own site in April. All the groups and individuals involved have publicly denied any wrongdoing. Last week Ronaldo’s management team released his 2015 tax declaration. It revealed he held assets outside of Spain worth more than $216 million. "This communication, which was not required by law, constitutes irrefutable proof that Cristiano Ronaldo and his representatives are in good faith, and cooperate with the authorities in a spirit of transparency and compliance with legality," Gestifute said. El Mundo said Tuesday the tax agency had contacted its parent company Unidad Editorial, and asked for information regarding 37 individuals, including Ronaldo. The newspaper said it will speak to its lawyers before responding, saying it had to strike a balance between protecting its sources and providing information to ensure justice prevailed. The tax office declined to name any of the individuals for which it has requested the information from El Mundo, citing privacy and Spanish law, which prohibits releasing private tax information. El Mundo said it has 10 days to respond to the agency’s request. Ronaldo isn’t the first soccer star playing in Spain to have his financial affairs come under scrutiny. The latest case comes four months after Ronaldo’s rival for the title of the world’s top player, Lionel Messi, was sentenced to 21 months in prison for tax fraud. Messi is appealing the sentence. (Tariq Panja and Maria Tadeo/Bloomberg)