American Express generally charges the most. They get away with it with breaks for small businesses and arguing that Amex customers will spend substantially mor

American Express generally charges the most. They get away with it with breaks for small businesses and arguing that Amex customers will spend substantially more in the shop when they come in. Visa and Mastercard’s merchant fees vary depending on what card it is. For most cards issued through those networks, the fees are lower than AmEx’s but for the highest end Visa Infinite (like the Sapphire Reserve) the fees are higher than AmEx’s. According to the merchant agreement, if you the merchant take any Visa’s you have to take all of them.