Two former Bank of America traders were convicted on 4 August of rigging precious metals prices by using an aggressive tactic known as spoofing, the latest win for prosecutors in a yearslong effort to crack down on the practice.

A federal jury found Edward Bases and John Pacilio guilty of wire fraud and conspiracy charges after a two-week criminal trial in Chicago. The proceeding was a test of prosecutors’ efforts to punish spoofing activity that predated a law defining the tactic and making it illegal.