Commercial litigation law firm Harcus Parker is set to bring the claim at the Competition Appeal Tribunal (CAT) on behalf of UK businesses in a case that could seek at least £7.5 billion in compensation, says Sky.The law firm will argue that the interchange fees are set by Visa and Mastercard, not market forces. Thomas Ross from Harcus Parker tells Sky: "These fees are unlawful and should be abolished."Businesses with an annual pre-Covid turnover of under £100 million will be automatically included in the claim unless they choose to opt out. Firms with a higher turnover are invited to opt in.Last year, the law firm brought a similar suit against Visa and Mastercard seeking compensation for businesses charged MIFs for accepting payments using corporate credit cards.Mastercard is also facing a £14 billion class action suit over interchange fees brought on behalf of British shoppers.