Four-weight world champion Saul ‘Canelo’ Alvarez is suing streaming service DAZN and promoter Oscar de la Hoya for at least $280m (£216m).
Papers filed with the US district court in California state the Mexican is suing for “breach of the single largest contract in the history of boxing”.
In 2018, Alvarez signed a $365m (£282m) deal for 11 fights on DAZN.
Alvarez’s claim details 11 complaints, including breach of contract, negligent interference and fraud.
The legal papers – seen by BBC Sport – request a jury trial and state DAZN and De la Hoya’s Golden Boy Promotions organisation have “broken the promises they made to each other, Alvarez, and boxing fans”.
At the time of Alvarez signing his fight contract, those close to the deal said it was one of the most lucrative not only in boxing but in all of sport.
The court documents state that after the first of his 11 fights was completed, DAZN would pay Golden Boy Promotions $40m for each of the remaining 10 bouts and $35m would be passed on to the fighter on each occasion.
Three of the 11 contests have now taken place but with no agreement reached for a fourth, 30-year-old Alvarez claims DAZN replied to a letter sent by his team in June stating the $40m fee would not be paid to Golden Boy Promotions for his next contest.
This alleged lack of payment has prompted him to sue both parties for breach of his contract and he is pursuing “at least $280m” in damages.
The case filings claim that DAZN cited the fact Alvarez had not fought Gennady Golovkin in 2019 as one of the factors in its decision to not pay him for his next bout.
DAZN insists the deal it struck with Golden Boy Promotions included approval rights on the fighter’s future opponents.
Alvarez claims his original agreement with Golden Boy “did not mention that DAZN would have any right to accept or reject any opponents”.
He is therefore taking action against Golden Boy Promotions for fraud-concealment, alleging the company made promises or representations to DAZN that were inconsistent with the contract he signed.