Big question. If they setup a hedge fund and bought the data from the card issuer, and did the exact same thing. Would it be legal? Don't they use private satellites to take pictures of mall parking lots and crop fields to estimate holiday sales and crop yields? Hows is this different. Its data that public doesn't have access to.
You're describing a world in which said data is available on the market, which is already a drastically different world than the one we live in. I would be surprised if they can legally sell that data - surely credit cards come with a privacy clause?
