Wonder how much of that 8 billion in payments/year they see. 2.75% (their fee) of 8 billion is 220 million. How much of that do they have to pay out to the payment networks?
A lot of that depends on their average transaction size. Square charges a flat rate despite there being per transaction fees, so 10 $1 charges are a lot less profitable for Square than 1 $10 charge.
They almost certainly actually lose money on the $1 transactions (their fee is under 3 cents but you'd typically have north of 20 cents of interchange fees).
