Two teenagers have pleaded not guilty to carrying out a cyber attack on Transport for London (TfL).
Thalha Jubair, 19, and Owen Flowers, 18, were arrested in September as part of an investigation by the National Crime Agency (NCA) and City of London Police.
Prosecutors said the alleged cyber attack resulted in a £39 million loss for TfL as well as a "loss of livelihood" for people dependant on TfL licences, Westminster Magistrates' Court heard in September.
The two defendants are charged with conspiring together to commit unauthorised acts against TfL.
The alleged attack posed "significant risk" to the UK economy and London residents, the court was told previously.
Flowers, of Walsall, West Midlands, who was first arrested over the TfL attack in September 2024 and then arrested again in September this year, is also charged with targeting US healthcare firms.
He is accused of conspiring with others to commit unauthorised acts against SSM Health Care Corporation and attempting to commit unauthorised acts to Sutter Health.
Jubair, from Tower Hamlets, east London, faces an additional charge under the Regulation of Investigatory Powers Act (Ripa) of failing to disclose the Pin or passwords of his devices.
They appeared at Southwark Crown Court on Friday and pleaded not guilty to all charges.
The NCA previously said investigators believe the TfL cyber attack was carried out by the criminal hacking collective known as Scattered Spider, which has been linked to other cyber attacks on Jaguar Land Rover and retailers including Marks and Spencer.
Transport for London identified that there had been a cyber attack on September 1 last year, in which customer details including names, contact information and Oyster card refund data including bank details were accessed.
Judge Christopher Hehir said a trial date of June 8 had been identified.
Both defendants are next due to appear at Southwark Crown Court on February 13 for a pre-trial review.
