Just one-sixth of European equities are traded away from exchanges, according to research from the Association for Financial Markets in Europe, which is aiming to debunk the belief that the over-the-counter, or 'dark' market, is ballooning out of control.

The AFME study, The Nature and Scale of OTC Equity Trading in Europe, said that the size of the European OTC equities market has previously been over-stated and that it actually accounts for 16% of equities trading.