What did they charge it to? How did Amex know who it's going to?
Mostly Plastiq. PayPal Key coded as a debit card which is only 1% charge for payments. Using the Amex business blue which gives 2x MR per dollar for example (up to 50k) and paying the card gets you 1.5% profit on every dollar you pushed through (there are ways of cashing out MR at 1.5).
Then things got really weird when Amex started coding PayPal Key as a 4x restaurant category, and started giving out an extra 3x MR per dollar if you referred others for a card. If you had an unlimited ATM machine in your living room wouldn’t you withdraw millions per week? And if you were an issuer would you notice if someone was suddenly cycling millions through one merchant? Well, Amex did notice those massive numbers (surprise) and decided shock and awe was the way to go.