Navinder Singh Sarao, the British high-frequency trader who was arrested over suspicions that he manipulated the futures market which sparked the May 2010 "flash crash", has been denied bail and will continue to be kept in custody.
The 36-year old from Hounslow, London would have been granted bail if he could pay £5m (€6.9m, $7.7m) and meet other conditions.
His lawyer, Joel Smith, told Westminster Magistrates court that he was unable to meet the terms and "invites no further order from the court in that regard".
District Judge Jeremy Coleman told Sarao and the court: "You have not met the conditions of bail as yet so I rebail you on exactly the same conditions as before. If you meet those conditions, you will be released, if you do not then you will be back here on May 6."
Sarao has been charged by the US Justice Department with one count of wire fraud, 10 counts of commodities fraud, 10 counts of commodities manipulation and one count of spoofing - the term for bidding with the intent to cancel.
He could face a sentencing of up to 380 years in an American prison. Wire fraud, commodities fraud and manipulation, and spoofing carry punishments of 10 to 25 year prison sentences per count or a $1m fine in the US.
An extradition hearing is set to take place on 24 & 25 September.