Goldman Sachs, HSBC, Standard Bank, and German chemical maker BASF have been accused of manipulating platinum and palladium prices in a lawsuit filed in New York by a jeweller.

The four companies colluded since 2007 to manipulate the twice-daily price "fixes" for the metals, said lawyers for Modern Settings, a jewelry and law enforcement badge-making company in Sarasota, Fla. The alleged price rigging allowed the four to enrich themselves at the expense of other market participants, the lawsuit said.