It has happened several times since 2008. Regulators propose a raft of new rules aimed at cleaning up some corner of the financial system. Industry groups fight back, saying the rules are bad for business. Usually, some sort of middle ground is reached.
But in few cases has the debate been so heated, and the reaction from industry so furious, as in the current controversy over the commodities provisions of the European Union's new Markets in Financial Instruments Directive (Mifid II).