10%? LOL, maybe on the worst acquirers for small, high-risk businesses. But most of those are eligible for Square at 2.75%. Large businesses, it's under 2%
Terms between Visa/MC/Amex and the retailer vary from business to business and country to country. Ever wondered why a lot of smaller businesses have a "$5 or $10 minimum for credit card"? That's because in certain agreements, Visa charges a flat 50 cents for any amount below $50, and then 1% or 2% above that. That's effectively 10% on a $5 transaction.
Again it varies, but please spare with me your condescending uppercase "LOL"