A US investment management firm is suing the five banks that set the London benchmark gold price, alleging that they conspired to manipulate the price of gold for their own gain.

The law firm Hausfeld, based in Washington, DC, filed a suit Monday on behalf of AIS Capital Management, alleging that from January 1, 2004 to the present day Barclays, Deutsche Bank, HSBC, Bank of Nova Scotia and Societe Generale "combined, conspired, and agreed with one another and unnamed co-conspirators to manipulate the prices of gold and gold derivatives contracts." The complaint seeks class-action status.