There is differentiation between banks. This is from forbes: "Also Wells Fargo’s average cost of deposits at 0.35% was the lowest in the industry and half of th

There is differentiation between banks. This is from forbes: "Also Wells Fargo’s average cost of deposits at 0.35% was the lowest in the industry and half of the peer average of 0.70% in 2010 making its cost of funding the lowest in the industry." I'm not 100% sure why they get that- whether it has to do with capital levels or Moody's ratings or what, but it has been cited by Buffett as one of their sustainable competitive advantages.