New European regulations forcing the separation of institutional investors' payments for trading and research could leave brokers at risk of losing up to half of their share dealing commission revenues.

Of the €3.4 billion in total commissions on European equity trades that institutional investors paid to brokers during the 12 months to March 31, 52%, or roughly €1.7 billion, was spent on compensation for research, according to a Greenwich Associates report on September 10 entitled Payment for Research: The Calm Before the Storm.