Square is basically trying to buy marketshare right now.
Everyone regardless of size pays the same base prices to Visa and Mastercard [1] and makes up profit in markups. A large processing network can charge lower markups because they process many more transactions, where smaller processors needs to make more on each. Smaller processing networks also make money on fees (chargeback fees for example), but Square does not.
The only way to profitability would be to try and shift transactions off the processing networks (like with Square Wallet), or to 1000x transaction volume.
Everyone regardless of size pays the same base prices to Visa and Mastercard [1] and makes up profit in markups. A large processing network can charge lower markups because they process many more transactions, where smaller processors needs to make more on each. Smaller processing networks also make money on fees (chargeback fees for example), but Square does not.
The only way to profitability would be to try and shift transactions off the processing networks (like with Square Wallet), or to 1000x transaction volume.
1. http://usa.visa.com/download/merchants/visa-usa-interchange-...