[gsibble]

Most of those very high reward rate cards come along with significantly higher interchange fees (4-5% or even higher). Merchants abhor them.

[nkurz]

I'm dubious. I just glanced at my interchange plus billed Merchant Account Statement, and the highest I saw was 2.95% + 20 cents for a couple international business rewards cards. I suppose you could count this as 5% for an under $10 purchase, but do you have a specific example of a card that exceeds 4% on larger transactions?