CHICAGO (AP) — An Australian commodities trader has pleaded guilty in Chicago federal court to manipulating market prices by placing orders in the millions of dollars and canceling them within milliseconds to sell smaller orders at a profit.

Jiongsheng “Jim” Zhao pleaded guilty Wednesday to one count of spoofing. Prosecutors say the 31-year-old executed trades on the Chicago Mercantile Exchange online from Sydney.

His arrest in January was part of what the U.S. Justice Department said at the time was part of “the largest futures-market criminal enforcement action” in department history. At least seven others were charged around the same time.

Zhao’s Chicago lawyer, Theodore Poulos, told the judge his client made just $21,000 from the illegal trades. He said he and prosecutors would recommend a one-year prison sentence. Sentencing is July 19.