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* Dark pools' share of European equity trading rises in Sep
* Outgrow "lit" exchanges
* Shrug off U.S. probes into industry
By Francesco Canepa
LONDON, Oct 1 (Reuters) - Dark pools, the anonymous tradingvenues at the centre of a series of investigations by U.S.authorities, continued to gain equity trading at the expense ofpublic exchanges in Europe last month, Thomson Reuters datashowed.
Dark order books, which permit shares to be bought and soldwithout publicly informing the market until the trade iscompleted, accounted for 6.9 percent of total European stocktrading last month, up from 6.4 percent the month before and 5.7percent a year earlier.
Around 53 billion euros ($66.95 billion) worth of shareschanged hands in dark pools in September, up 20 percent from theprevious month and 29 percent year on year. This compares withjust 250 million euros in January 2008.
Dark pool trading has been rising despite growing scrutinyby regulators, who are concerned that brokers and proprietarytrading firms that use aggressive high-frequency tradingstrategies have an unfair advantage over other clients.
Since June, U.S. authorities have begun investigating darkpools operated by a number of European and U.S. banks, includingSwitzerland's UBS and the United States' Goldman SachsGroup.
UBS Multilateral Trading Facility, BATS Chi-X Europe andTurquoise were responsible for roughly half of all ordersexecuted on "dark" books last month.
Dark pools' share of total market turnover may still besmall, but they have been growing faster than "lit" order books- where live trade data is published - operated by primary stockexchanges and various other firms.
Equity turnover on these "lit" order books rose 5 percentyear on year in September to 714 billion euros, but it remainsdown from over a billion in 2008. Total turnover across dark andlit order books was up 7 percent last month to 767 billioneuros.(1 US dollar = 0.7916 euro) (Reporting By Francesco Canepa; Editing by Larry King)
