A dozen banking giants have been sued in New York for allegedlyfixing global foreign exchange rates in the latest ripple to accompany governmentprobes of the huge market.The defendants in the class-action lawsuit, which include BNP Paribas and JPMorganChase, shared confidential information during private online chat sessions tocollude and fix trades on the key WM/Reuters foreign exchange rate, which is seteach afternoon in London, according to a complaint filed Monday.The conspiracy "impacted the pricing of trillions of dollars' worth of FX Instruments,inflicting severe financial harm on Plaintiffs and members of the Class," thecomplaint said.The complaint did not quantify the losses, calling the impact of the rate-fixing"presently undetermined."The other defendants in the case are: Bank of America, Barclays, Citigroup, CreditSuisse, Deutsche Bank, Goldman Sachs, HSBC, Morgan Stanley, RBS and UBS.A dozen plaintiffs are in the class-action suit, which amends and expands a November 2013 suit against seven banks filed by Haverhill Retirement System ofHaverhill, Massachusetts.The 11 plaintiffs that joined the original lawsuit Monday include Aureus CurrencyFund, a California investment fund, the City of Philadelphia and the OklahomaFirefights Pension and Retirement System.Defendants in the case are "dominant" dealers in foreign exchange, with about 84percent of  market share with transactions worth some $5.3 trillion per day.The complaint called foreign exchange "one of the world's least regulated financialmarkets" and rated it an "opaque" system because most trading takes place awayfrom exchanges.The suit comes as regulators in the United States, the European Union, Britain andother venues launch probes of foreign exchange market manipulation.Banks have suspended or fired more than 30 employees in the wake of these probes,according to the complaint.