[ by Howard Haykin ] While much of the scrutiny surrounding interest rate manipulation has centered on Barclays, regulators have said that traders at the big British bank colluded with rivals to influence a key benchmark. Regulators refer to a 3-year scheme, where a senior Barclays trader in Europe supposedly worked with at least 4 counterparts at other banks:  (i) Crédit Agricole, (ii) HSBC, (iii) Deutsche Bank and (iv) SocGén, according to unidentified sources.  Regulators have been examining to determine whether evidence exists to prove that at least one other bank was involved. Objective of Manipulation. Traders, in an effort to bolster their profits, collaborated to push interest rates up or down, according to regulatory documents.  By doing so, they aimed to eke out extra gains on their trades or to limit losses.  In its complaint against Barclays, the CFTC described the bank's trader as having "orchestrated an effort to align trading strategies among traders at multiple banks" to profit on their portfolios. As the rate-manipulation scandal spreads to other banks, the fallout could have major ramifications for the financial industry.  Civil and criminal authorities around the world are investigating, and U.S. lawmakers have started their own inquiries.  The civil and criminal actions, as well as private lawsuits, could cost the banks tens of billions of dollars. The Barclays case centers on key benchmarks, including the London interbank offered rate, or Libor, and the Euro interbank offered rate, or Euribor. Such rates are used to determine the borrowing costs for consumers and corporations. The senior trader at Barclays who worked with the four European banks specifically tried to manipulate Euribor, according to regulators. The Barclays case was the first to emerge from the multi-year investigation, which has also touched some of the biggest banks on Wall Street.  Authorities in the United States, Britain, Japan, and elsewhere are also looking into the potential involvement of JPMorgan Chase, Citigroup, and UBS.  The Financial Times previously reported the names of the 4 European banks that worked with the Barclays trader. The broad investigation has prompted outrage from lawmakers in Washington and London. In recent weeks, British central bankers and regulators testified to Parliament about their role in the rate-manipulation scandal.  In the United States, politicians are asking why regulators did not stop the illegal activities, even though regulators knew about potential problems as far back as 2007. The United States Congress is also delving into the matter, as lawmakers question why the rate-setting process was not better policed.  Representative Randy Neugebauer, the Republican chairman of the House subcommittee investigating Libor, is seeking documents from the New York Fed about JPMorgan Chase, Citigroup, and Bank of America, the 3 American banks involved in setting the rate.  Last week, Mr. Neugebauer collected transcripts from at least a dozen phone calls in 2007 and 2008 between New York Fed officials and executives at Barclays. The House committee has also homed in on Barclays.  On Monday, Congressional staff will receive a briefing about Libor from the general counsel of Barclays in America and its chief lobbyist, according to a government official. For further details, go to:  [Dealbook, 7/18/12].