Offer your insights or judgment on the input financial query or topic using your financial expertise. Reply as normal question answering

How can I stop a merchant from charging a credit card processing fee?
I gather that, while it is not illegal for a merchant to pass their payment card processing fees on to their customers directly in the form of a surcharge, doing so is a violation of their merchant agreements with the payment card processor (at least for Visa/MC). It's not - surcharging has been permissible since 2013, as a result of a class action lawsuit against Visa and MC. It's still prohibited by state law in 9 states.  If you're in one of those 9 states, you can contact your state Attorney General to report it. If you're not, you can check to see if the business is complying with the rules set forth by the card brands (which include signage at the point of sale, a separate line item for the surcharge on the receipt, a surcharge that doesn't exceed 4% of the transaction, etc.) and if they're in violation, contact the card company. However, some of those rules seem to matter to the card companies more than others, and it's entirely possible they won't do anything. In which case, there's nothing you can really do.