The European Commission said on Tuesday it had informed Credit Agricole, HSBC and JPMorgan of its reasons for believing they rigged interest rate benchmarks crucial to global financial markets.
Following a probe, the Commission said it had now told the three of its "preliminary view that they may have breached EU antitrust rules by colluding to influence the pricing of interest rate derivatives denominated in the euro currency."
Such action was "aimed at distorting the normal course of pricing components for euro interest rate derivatives," it said in a statement.
If the suspicions are proved, the three would be in breach of European Union rules which prohibit anti-competitive business practices.
In response, both HSBC and JPMorgan said they would defend themselves forcefully while Credit Agricole said it would study the Commission statement.
In December, the EU imposed a record 1.7 billion euros ($2.3 billion) in fines on six global lenders, including Deutsche Bank, France's Societe Generale and Britain's Royal Bank of Scotland, for their role in fixing interest rates used to set the price for a wide range of loans and investment instruments.
EU Competition Commissioner Joaquin Almunia said at the time that the fines were intended both to "punish and dissuade" other lenders as part of efforts to restore order to the financial services industry after the excesses of the 2000s led to the bust and collapse of 2007-08.
In the fallout, authorities in Europe, the United States and Japan, as well in many other financial centres, have probed the banks' role in setting prices for interest rate, foreign exchange and commodity instruments.
The result has been huge fines and a tightening up in bank regulatory standards in order to prevent further abuses and ensure that lenders do not get caught up in the sort of speculative frenzy which left so many exposed and needing taxpayer bailouts at the height of the financial crash.
Tuesday's statement is the next step in a Commission inquiry and will allow HSBC, JPMorgan and Credit Agricole to make a formal response to the allegations.
The Commission noted that the sending of its "statement of objections" to the three "does not prejudge the final outcome of the investigation."
A company found at fault under EU anti-trust provisions can be fined up to a maximum of 10 percent of its annual sales, a potentially huge sum in the case of the banks.