More than 60% of all purchases last year were made with a credit or debit card, according to the Federal Reserve. That’s up from 45% in 2016. That means big money for credit card companies, which made more than $187 billion last year in processing fees alone.

For businesses that take credit cards — especially smaller ones — it’s an increasingly large expense.

Mac Hay owns a bunch of seafood restaurants and markets on Cape Cod in Massachusetts, and he said that credit card swipe fees are sort of like taxes.

“You just kinda take it as a fact. It’s sort of like, ‘Well, I guess we’re going to have to pay them. We’re going to have to pay the credit card processing fees,'” he said.

More than 90% of his customers pay with a card. It’s not like he’s not going to take them, so he doesn’t think about it much.

That is until the end of the month comes around, “and I see what we pay in credit card fees — it’s astronomical.”

Restaurants tend to have thin profit margins — maybe 5% or 10%.

For many, paying between 2% and 4% of every sale to process a card is tough, according to Erika Polmar, executive director and a cofounder of the Independent Restaurant Coalition.

“I talked to a restaurant last week who is paying $15,000 in swipe fees a month,” she said.

Bigger businesses can often negotiate slightly lower fees, but small ones don’t have the leverage.

Plus, “Visa and Mastercard dominate the credit card market in the U.S.,” Polmar said. “80% of credit card transactions are going through those two processors.”

So, she added, there’s not much pressure to offer competitive rates.