“The effect of these artificially inflated fees—assessed to and paid by Square—is higher retail prices paid by consumers economy-wide,” Block said in the suit. “As retail prices increase in response to inflated fees, consumers can afford less and thus purchase less, reducing output.”

https://news.bloomberglaw.com/banking-law/visa-mastercard-hit-with-antitrust-suit-over-credit-card-fees-1?stream=top