LONDON – A London judge sided with U.K. grocery chain Sainsbury in its lawsuit against MasterCard, ordering the credit-card firm to pay the retailer $90.8 million, MarketWatch reports.

The judge found MasterCard had set too-high interchange default fees, leaving merchants with few options other than to allow cards from all credit card issuers. That left MasterCard with the authority to put unilateral rates in place that were more than they would have been if the retailer could have negotiated with MasterCard.

Retailers who find the default rate too onerous had only “unattractive alternatives,” the judge wrote, including filing complaints, refusing to accept certain cards, or tacking on surcharges to card users. Other U.K. merchants have filed similar lawsuits against MasterCard.

The judge also said that transaction fees should be 0.5% for credit cards (instead of 0.9%) and 0.27% for debit cards (instead of 0.36%). The judge based the damage amount on those rate differences.

In June, a U.S. federal appeals court overturned a $7.25 billion antitrust settlement between Visa, MasterCard and millions of retailers after the court found some merchants included in the pact hadn’t been represented adequately. That ruling related to the fees retailers had to pay when accepting cards and the regulations imposed as conditions from MasterCard and Visa.

In response to the ruling, NACS CEO Henry Armour said, “We are pleased that the Second Circuit Court of Appeals has thoughtfully addressed the problems we have long identified with this proposed settlement. We will work to help ensure that this moves forward in a way that recognizes the best interests of merchants and the consumers they serve.”