At the risk of being dense, are you sure you're not talking about debit cards? I've never seen interchange fees lower than about 1% for credit cards. In what I read from the Durbin Amendment, I've only found the specific numbers you mentioned in reference to debit cards.
If I'm wrong, I want the name of your merchant processor!
I am most definitely talking about debit cards. I said "fee for charging a debit/check card". They make up 25% of my online processing volume despite being a mostly B2B business. They're probably more than 25% of Stripe's volume.
Whoops, you did say that, way back in the first post in our thread. Sorry, I've been focused on credit cards — all is clear now. I hadn't thought at all about that wrinkle of Stripe.
I suppose it's (only partially) balanced by the higher AMEX, etc fees.
If I'm wrong, I want the name of your merchant processor!