Mastercard (NYSE:MA) has suffered a setback in a potentially damaging case being heard in Europe. The U.K. Supreme Court rejected the company's request to force individual suits over interchange fees in the country, rather than the 14 billion pound ($18.5 billion) class action case currently being considered. The vote on the request was close, with three of the five ruling judges voting against it, and two in favor.

The sprawling lawsuit alleges that the intra-European merchant interchange fee Mastercard charged for personal cards restricted competition in the market over a 16-year period ending in late 2007.

The European Commission -- the governing body of that continent's European Union economic bloc -- made such a ruling in December 2007. In the U.K., it was used as the basis of a case brought by a government ombudsman to a lower court in 2016.

A person holding three credit cards fanned in their hands.

Image source: Getty Images.

Interchange, or "swipe," fees are critical in the payment card business. They are a small percentage of every sale charged to the merchant selling the merchandise or service.

Mastercard first unsuccessfully challenged the European Commission's findings. It has since switched its legal strategy to one of challenging the validity of the class action suit.

If the court ends up awarding the class the entire amount, each of the 46.2 million parties in the class action lawsuit will receive 303 pounds ($401). 

Mastercard has not yet commented on the latest development in its case. While losing it would undoubtedly be a financial setback, the company generates mounds of cash and would likely be able to recover before long. As of the end of its most recently reported quarter, it had over $11.2 billion in cash and equivalents.