U.S. officials are investigating at least 10 major banks for the possible rigging of precious-metals markets, according to The Wall Street Journal.
It comes despite European regulators dropping a similar probe after finding no evidence of wrongdoing.
Prosecutors in the Justice Department's antitrust division are analyzing the price-setting process for gold, silver, platinum and palladium in London, while the Commodity Futures Trading Commission (CFTC) has opened a civil investigation, the WSJ reported, citing "people close to the inquiries."
The agencies have made initial requests for information, and HSBC said in its annual results Monday that it had received a subpoena from the CFTC relating to precious-metals trading.
Also under scrutiny are Bank of Nova Scotia , Barclays , Credit Suisse, Deutsche Bank , Goldman Sachs, J.P. Morgan, Société Générale, Standard Bank and UBS, according to the newspaper's sources.
Bank representatives contacted by the WSJ declined to comment or couldn't be immediately reached. A CFTC spokesman declined to comment, as did a spokeswoman for the Justice Department.