That settlement, stemming over a long-running case involving what are known as interchange fees or “swipe fees,” was the subject of a federal court hearing Monday (April 27).

As Bloomberg News reported, groups representing major retailers such as Walmart told U.S. District Court Judge Brian Cogan they oppose the settlement. Cogan did not rule on the matter, the report added, but said he will issue a written ruling in the future.

According to the report, many retailers want to make deals with the card companies on their own. Attorney Debra Greenberger, representing the National Retail Federation and Retail Industry Leaders Association, told the court merchants would rather take the case to trial and risk losing than hold to the terms of the settlement.

“Be careful what you wish for,” Cogan said.

Visa and Mastercard have been locked in a two-decade long battle over the fees merchants pay to accept credit cards.

The two companies announced a proposed settlement in November. Under that agreement, Visa and Mastercard would lower interchange fees — typically set at 2% to 2.5% — by 0.1 percentage points for five years.

Merchants would be allowed to choose whether they want to accept U.S. cards in certain categories such as commercial cards, premium consumer cards including many popular “rewards” cards, along with standard consumer cards.

The settlement is said to save merchants upwards of $200 billion over eight years by giving them the chance to reject higher-cost cards. However, Bloomberg said, that eyebrow-raising sum has attracted opposition from both big box retailers and smaller merchants.

The report cites a note from Keefe Bruyette & Woods analysts who said Cogan, based on his body language, seemed to be leaning toward approving the deal.

Meanwhile, PYMNTS wrote last week about another interchange fee battle playing out in Illinois, with banking groups and the Office of the Comptroller of the Currency (OCC) objecting to a state law — slated to go into effect July 1 — that would block the collection of interchange on portions of transactions tied to taxes and tips.

“The case carries implications that extend beyond Illinois,” PYMNTS wrote. “Legislative proposals in other states such as Colorado and Delaware indicate that similar approaches to interchange could follow, raising the prospect of divergent rules across jurisdictions.”

If the court upholds the Illinois law, financial institutions would have to adapt their systems to accommodate state-specific fee calculations, the report added.