The Madrid court's ruling, which was seen by Reuters on Tuesday, found nothing unlawful in the "LaLiga Boost" deal, in which 38 Spanish clubs voted to receive cash in return for handing an 8.2% stake to CVC Capital Partners.
The deal involved creating a new company with CVC's participation to garner revenue from LaLiga broadcasting and sponsorship rights for 50 years. It was approved in late 2021.
It was the first investment agreement by a private equity firm in a major European league, but Real Madrid and Athletic filed a complaint in January 2022 saying it would cause irreparable damage to the entire Spanish soccer sector and violated Spanish sports law and LaLiga's statutes.
Real Madrid and Athletic did not immediately reply to a Reuters request for comment.
The court ruling can be appealed.
In a statement, LaLiga welcomed the judge's decision, pointing out that the deal has allowed the majority of its clubs to make investments without state aid.
Clubs have spent most of the 1.9 billion euros, mainly on stadium improvements, reducing debt and investing in their professional teams.
