A co-worker complained recently that the rate on his credit cards had just doubled — to more than 20 percent — for no particular reason. He said he had no late payments or other problems, and that a customer service rep had told him the rate hike was a “business decision.”

My guess was that the rate hike was linked somehow to the liquidity crunch and CDOs. His card carrier does have a consumer banking unit (the “what’s in your wallet” guys) but I doubt their deposits cover more than a tiny fraction of their lending.