Tom Hayes, the first person to be found guilty of Libor rigging in the UK, is suing the City watchdog to overturn a ban on him working in the industry.
The former UBS and Citigroup trader was jailed for 14 years in August 2015, but his sentence was reduced to 11 years by the Court of Appeal in December the same year.
He recently launched an application to the Criminal Cases Review Commission (CCRC) to further investigate his case, after his appeal to the Supreme Court was blocked last year.
Now, Bloomberg has reported the former trader will also be representing himself before the upper tribunal in a bid to overturn a ban from the Financial Conduct Authority (FCA) to prevent him working in the industry. Court listings confirm Hayes filed a case on 23 December.
The FCA declined to comment.
Hayes told a court hearing last year that he had lost nearly everything trying to trade to earn his first batch of legal fees.