Why do most U.S. banks shut the door on 'open banking'?

On Jan. 13, banks in the European Union will become the leaders of the so-called open banking movement, allowing access to customer account data for any third-party service provider their customers approve via a dedicated communication interface. The move is the fruit of the second Payment Services Directive (PSD2), which the European Commission says will "facilitate innovation, competition and efficiency," give consumers more and better choice in the EU retail payment market, and introduce higher security standards for online payments. In the U.S., however, open banking is largely ad hoc and more of a workaround. A few large banks, such as Wells Fargo and JPMorgan Chase, have made bilateral agreements with data aggregators and accounting software providers. The rest have mostly opted out.