There’s a fight going on in foreign exchange. As their margins shrink, big FX dealers are warning multi-dealer platforms (MDPs) and liquidity aggregators to lower their prices or be cut out of the market.

Over the past six months it hasn’t much mattered which bank you speak to – sooner or later every conversation works its way round to the same grievance, and the same ultimatum.

“Two things can happen here: either the pricing models of MDPs come down to reflect the underlying economics of the