The high-frequency futures trader who stands accused of contributing to the stock market "flash crash" in May 2010 told a London court Wednesday that he did not consent to extradition to the U.S.
He was granted conditional bail by Westminster Magistrates' Court, which was set at £5 million ($7.5 million).
The U.S. Justice Department has charged Navinder Singh Sarao, 36, of West London, with wire fraud, commodities fraud and manipulation, and one count of "spoofing"—when a trader places a bid or offer with the intent of cancelling it before execution.
During the proceedings, District Judge Quentin Purdy said that Sarao faced serious criminal charges and had "clearly upset the Americans, to put it mildly."
Sarao was arrested Tuesday in Britain. U.S. authorities have requested his extradition to stand trial in America, following claims that his actions helped cause the stock market crash that saw the Dow Jones industrial average plummet 1,000 points on May 6, 2010.
Sarao told the court Wednesday that he did not agree to the extradition. Purdy set Aug. 18 and 19 as provisional dates for a full extradition hearing.
The conditions of bail state that Sarao must stay at his home address, have an electronic curfew at night and no access to the Internet.
A person who answered Sarao's phone told CNBC earlier Wednesday that he did not want to comment.