So first of all the Volcker Rule, which I presume is what you were referring to? prohibits banks from taking principle positions to profit on directional trades and it absolutely includes forex. It does not prohibit market making, you are correct on that and I should have included that. Interestingly, since until a few months ago IB's subsidiary Timber Hill engaged in market making, my analogy was still pretty dead on. My point being the big banks aren't trading to make money on the direction of forex anymore, while they once did, which is something not everyone seems to be aware of. If you were aware of it, great, have a great weekend!