Grupo Modelo, the Mexican brewer, made good on its threat to request arbitration over a $52bn deal for its part-owner Anheuser-Busch (NYSE: BUD - News) to be acquired by InBev, but InBev and Anheuser expected the claims to have no impact on their ability to close their merger by the end of the year.

Modelo has argued since the deal was inked this summer that under a 1993 agreement governed by Mexican law, Anheuser cannot transfer ownership of its half stake in Modelo without giving Modelo the chance to buy itself back.

InBev and Anheuser disagree, and one person close to the companies dismissed Modelo's request for arbitration as "fairly tepid," noting that Modelo had not petitioned to stop the deal through an injunction.

"They may have felt, given their threats, that they had to do something, but didn't want to do something that was too disruptive," the person said. The deal is already trudging toward closure through a thicker morass than expected, thanks to the credit crunch.

Modelo's claim presented InBev's deal with its second new hurdle this week. On Tuesday, the Belgian-Brazilian brewing giant postponed a $9.8bn rights offering intended to help fund its purchase of Anheuser, and said it would wait for credit markets to stabilise before rescheduling the share sale.

InBev said it was confident that Modelo's claims were "entirely without merit," a sentiment echoed by Anheuser. Anheuser said it would contest the claims.