By Huw Jones
LONDON (Reuters) - The European Union will complete a fresh study of share trading data before drawing conclusions from a comprehensive review of market rules, an EU official said on Thursday, as exchanges demand more transparency from rival trading venues.
A reform of MiFID II, the EU's rules on trading stocks, bonds and other securities, has become more pressing after Britain's departure saw 6 billion euros a day of euro share trading shift overnight from London to the bloc last week.
But the plans have sparked a tussle between exchanges and the banks and asset managers, who are both their main customers and their competitors in some cases.
Exchanges argue that too much trading, about half the total according to some official estimates, takes place on "dark" venues or inside investment banks like Goldman Sachs, Barclays, Morgan Stanley and Credit Suisse, and want limits set.
"We need to fight for more transparency," said Rainer Riess, director general of the Federation of European Securities Exchanges, which represents bourses like Euronext and Deutsche Boerse.
But Tilman Lueder, head of securities markets at the European Commission, the 27-country EU's executive, said a closer look is needed before deciding on any curbs.
"We should drill a bit deeper into some of the data sets," Lueder told the FESE webinar. "We should look at what is the relevant market and maybe not take a decision on a dog's dinner of all kinds of trades."
When "technical trades" were filtered out, there is an encouraging increase in trades on exchanges, he said.
A new data analysis will be launched in the first half of this year with any proposals for changing the rules presented in the autumn, Lueder added.
Paul Hilgers, managing director at Deutsche Boerse Group, said that with 600 trading platforms in the EU, there is a need to simplify infrastructure to stop "free riders" that use exchanges for prices.
But Urban Funered, chief executive of the Swedish Securities Markets Association, said there was a need to avoid returning to the "good old days" of stock exchanges with national monopolies.
(Reporting by Huw Jones; Editing by Catherine Evans)