By Huw Jones
LONDON, Nov 9 (Reuters) - European Union lawmakers are set to back a tougher clampdown on "dark pool" and "high frequency" share trading on Tuesday in a vote that will shape EU securities law reforms planned for next year.
The European Parliament's economic affairs committee will favour hardening a report by British centre-right lawmaker Kay Swinburne by also taking a tougher line against "over the counter" (OTC) or off exchange trading of shares.
It dovetails with wider EU and global efforts to shine a light on all parts of the market after large pockets of opaqueness alarmed regulators tackling the financial crisis.
The amended report now directly blames a decrease in transparency on European stock markets on "an increase in dark pools and crossing networks".
So-called dark pools allow anonymous trading which is deemed unfair to other market participants who have less information with which to price assets.
The report also rejects arguments from banks that forcing some trades onto "lit" exchanges would damage some trades.
Half of OTC transactions are below the standard size and therefore do not require protection against market impact, the amended report says.
This rewording is welcomed by the bloc's bourses which have campaigned hard to amend a 2007 set of EU trading rules known as Markets in Financial Instruments Directive or MiFID.
"The parliament's work over the last few months appears to strongly endorse the role of transparency, which we welcome," said Judith Hardt, secretary general of the Federation of European Securities Exchanges.
Since MiFID was introduced, chunks of trading have migrated from exchanges to a clutch of new start ups, some of them known as dark pools.
Bourses say banks have also skirted MiFID rules by trading in-house on their broker crossing networks.
Swinburne's original report took a more moderate line but after negotiations with the other main parties it has been toughened up with broad cross-party backing.
EU Internal Market Commissioner Michel Barnier will propose legislative changes to MiFID early next year in light of the financial crisis, the impact of start ups, growth in computer or high-frequency trading (HFT), and the May 6 "flash crash" on Wall Street when blue chips went briefly into freefall.
Mary Schapiro, chairman of the U.S. Securities and Exchange Commission said on Monday there was a need to deal with algorithimic trading that "go crazy" on U.S. stock markets.
Britain's financial watchdog may unveil its own thinking on HFT later this month.
The EU assembly will have joint say with the bloc's governments on the MiFID reform and the report will form the basis for parliament's negotiating position.
An investment bank source said the report's push for appropriate supervision and regulation of broker crossing networks was broadly reasonable.
The amendments scrap Swinburne's push to carve out a new regulatory regime for broker crossing networks and instead insist they are regulated like other trading venues.
But the report could fuel wider "scare stories" about growth and influence of the OTC sector, the banking source added.
The report says up to 40 percent of trading in shares is done OTC and that market participants should be encouraged to transact more on trading venues so that off-exchange volume "declines substantially".
The report calls for the European Securities and Markets Authority, which will be launched in January, to probe the costs and benefits of algorithmic trading and HFT and their potential for abuses and impact on market stability.