Fresh charges have been issued against the so-called 'Hound of Hounslow' trader, as his extradition hearing was adjourned for five months.
Navinder Singh Sarao, who is accused of wiping £570bn from the US stock market in minutes during the 2010 'flash crash', was on Friday (September 25) re-arrested and served with a new warrant seeking his extradition to the US.
The 36-year-old, of Clairvale Road, Heston, who denies the charges, later appeared at Westminster Magistrates' Court, where his extradition hearing was adjourned until February 4.
The new charges against Mr Sarao differ only slightly from those on which he was arrested in April, with six months added to the start of the period over which his alleged crimes are said to have been committed.
Mr Sarao denies using an automated computer programme to illegally manipulate the US stock market, through which method the US government says he earned £27m over four years and £585,000 on the day of the crash alone.
He has previously said he has done nothing wrong except "being good at my job".
He is charged with 22 counts of fraud, manipulation and 'spoofing' - the practice of bidding or offering for shares with the intention of cancelling before the transaction can be completed, thus artificially altering share prices.
Mark Summers, representing the US government, told the court: "They [the fresh allegations in the new indictment] bring back the start date of the alleged criminal activities by six months.
"They include new factual allegations concerning the obtaining and customisation of the trading programme."
Mr Summers added that the allegations relating to the six-month period were about emails between the defendant and a programmer, and not any illegal trading said to have taken place during that time.
'His mental state is fragile'
Joel Smith, defending him, told the court the mental strain on Mr Sarao was beginning to show as the case drags on.
"It was disappointing to be be informed at about 9pm last night that a fresh request [for Mr Sarao's extradition] was being issued," he said.
"It was disappointing for Mr Sarao, who is understandably distressed by proceedings.
"It's been mooted before that he's been diagnosed with Asperger's syndrome, and his mental state is fragile. This [late submission of new allegations] adds to the stress these proceedings are causing him."
Mr Smith added that Mr Sarao's barrister Mark Lewis QC was unable to make it to court after injuring himself falling on his stairs that morning, making an adjournment unavoidable.
Mr Sarao, wearing a grey suit and purple shirt, sat with his head bowed for most of the proceedings.
He is next due in court on October 22 for a hearing to decide whether a US professor specialising in the financial markets should be permitted to give evidence, as requested by the defendant's lawyers.
District Judge Quentin Purdy told Mr Sarao two days had been set aside for his extradition hearing on February 4 and 5, but said these dates were subject to change.
He granted the defendant bail on the same conditions as before.