Navinder Sarao, the trader accused by US authorities of contributing to a 2010 flash crash, cannot appeal a ruling that he must be extradited to the US to face charges carrying a maximum sentence of 380 years.
At the High Court today, Lord Justice Gross said it was "clear" the court must turn down his application.
However, he could now appeal to the Supreme Court.
Hound of Hounslow
Use of the technique, known as spoofing, caused the Dow Jones Industrial Average to fall by several hundred points in a matter of minutes on 6 May 2010, before bouncing back almost immediately. Sarao is accused of making $900,000 (£735,000) on the day of the crash.
Sarao made a total of $40m (£28.3m) from trades using the technique between 2009 and 2014. Today Lord Justice Gross said the case was "about five years of alleged market manipulation, rather than [just] a flash crash".
He was dubbed the "Hound of Hounslow" because he traded from his bedroom in a quiet road in West London.
In March a judge ruled that Sarao must face charges, which carry a maximum sentence of 380 years, in the US.
US authorities have played an increasingly active role in policing global markets in recent years.
In March Barry Vitou, a corporate crime expert at Pinsent Masons, told City A.M. that the US was taking a "long arm" approach to law enforcement.
"The takeaway is: just because you are thousands of miles away, don’t assume that your actions will escape a prosecuting agency in the US, or for that matter in the UK."