Sport's international tribunal on Monday backed FIFA's ban on third-party player ownership but softened a suspension against Belgians Seraing, who have been at the heart of a legal battle over the issue.
FIFA banned third party ownership -- where an individual investor or company owns a player's economic rights -- in 2015, calling the practice a threat to the game.
The practice allowed third parties, rather than clubs, to buy and sell players and reap the associated financial benefits, which would otherwise have gone to clubs.
Seraing United were fined 150,000 Swiss francs ($150,000, 145,000 euros) and banned from making deals for four transfer windows in September of the same year for their links with Maltese-based firm Doyen in player deals.
The third division Belgian side has now failed with appeals to the Court of Arbitration for Sport (CAS), FIFA and in Belgian courts. They had claimed the FIFA regulations were illegal.
CAS said it had "confirmed the validity" of the FIFA regulations on transfers but that it "considered that the sanction imposed on the Belgian club was too severe".
The transfer ban was reduced to three windows meaning Seraing will be able to buy players again at the end of the 2016-2017 season.