The former head of collapsed bitcoin exchange MtGox apologised at closing arguments in his Tokyo trial on Thursday for losses that bankrupted the firm, local media reported. Mark Karpeles, 33, faces charges that he pocketed about 340 million yen (US$3.1 million) and fraudulently manipulated data related to MtGox. His trial began in July 2017 and the Tokyo District Court is expected to announce a verdict on March 15 next year. Karpeles denies all charges. MtGox – once the world’s biggest bitcoin exchange – collapsed in 2014 after cryptocurrency worth half a billion dollars disappeared from its virtual vaults, a mystery that remains unsolved. In early December, Tokyo prosecutors demanded a 10-year jail term for Karpeles, claiming his alleged acts “were extremely vicious, as they completely undermined confidence in trading.” Karpeles on Thursday apologised for failing to prevent the disappearance of the bitcoin but insisted he was not guilty of the charges he is facing, public broadcaster NHK said. Those charges are not directly related to how MtGox lost 850,000 bitcoin – worth about US$480 million at the time. MtGox was closed in 2014 after admitting the massive disappearance of the coins. The company initially said there was a bug in the software underpinning bitcoin that allowed hackers to steal them. Karpeles later claimed he had found some 200,000 lost bitcoin in a “cold wallet” – a storage device that was not connected to other computers. The French national – who cannot leave Japan as a condition of his bail – was originally arrested in August 2015. MtGox, which once said it handled about 80 per cent of global bitcoin transactions, filed for bankruptcy protection soon after the virtual money went missing, leaving a trail of angry investors calling for answers and denting the cryptocurrency’s reputation.