Thodex, one of Turkey’s largest cryptocurrency exchanges, collapsed on April 20, 2021, when founder and CEO Faruk Fatih Özer froze all withdrawals, suspended the platform, and boarded a flight to Albania — leaving approximately 391,000 registered users locked out of accounts holding funds estimated at roughly $2 billion. The exchange had operated since 2017 under the name Koineks before rebranding as Thodex in March 2020. Özer was 27 years old at the time of the exit.
Turkish prosecutors launched an immediate investigation. Özer was arrested in Vlora province, Albania in August 2022 after more than 16 months as a fugitive. He was extradited to Turkey in April 2023. On September 7, 2023, an Istanbul court convicted Özer and several of his siblings of aggravated fraud, money laundering, and criminal organisation charges, and sentenced him to 11,196 years in prison — one of the longest sentences ever imposed in Turkey. On appeal, the Istanbul Regional Court of Justice upheld the fraud and money laundering convictions in early 2025 but dismissed the organised-crime charge and ordered a limited retrial on that element. Özer remained incarcerated pending the retrial. On November 1, 2025, he was found dead in Tekirdağ F-Type High Security Closed Penitentiary. Authorities reported he was discovered hanged in the bathroom; the Istanbul prosecutor’s office opened an investigation and the body was transferred to the Institute of Forensic Medicine. The cause of death remained under formal inquiry at the time of this report.
The estimated loss figure of $2 billion, widely cited by Turkish prosecutors and international media, reflects the claimed value of cryptocurrency held in Thodex accounts at the time of the freeze. Because Thodex operated as a closed order-matching system without publishing audited proof-of-reserves, the true value of cryptocurrency under management has never been independently verified from blockchain records. The figure should be treated as the prosecutors’ working estimate rather than a fully audited loss amount.
MyCoin, a Hong Kong-based cryptocurrency trading operation, vanished in late January or early February 2015, leaving approximately 3,000 investors locked out of accounts they believed held Bitcoin contracts collectively valued at up to HK$3 billion (approximately US$386–387 million at prevailing exchange rates). The platform had presented itself as a Bitcoin trading exchange offering guaranteed returns of HK$1 million within four months on a standardised contract. In practice it operated as a pyramid scheme: early investors were paid from the deposits of newer ones, and the promised Bitcoin holdings either did not exist or were vastly overstated. When the scheme could no longer sustain itself, the operators — whose identities were never fully confirmed under publicly named directors — shut the platform without notice and disappeared.
Hong Kong’s Commercial Crime Bureau launched an investigation within days of the closure. Five suspects were arrested in Hong Kong in March 2015, including two brothers and three women charged with conspiracy to defraud. Separately, Taiwanese authorities arrested two linked suspects, including one individual later identified as a key operator in Taiwan, who was extradited back to face proceedings. Operators were also pursued in Thailand. The ROSTER entry for VT-004 records the status as Convicted, reflecting that legal proceedings against arrested operators concluded in conviction. Full public sentencing records in English were not available in the sources reviewed for this report; the convictions are established in published court records and press releases from Hong Kong and Taiwanese authorities.
MyCoin is significant as an early large-scale Asian exchange exit and as a case study in how traditional pyramid-scheme mechanics were adapted to cryptocurrency’s opacity and novelty. Its victim pool was concentrated among working-class Hong Kong residents recruited through established professional networks — real estate agents, insurance brokers, and legal firm clerks — who used existing client trust relationships to channel money into the scheme.
Bitgrail, a small Italian cryptocurrency exchange operated by Francesco Firano, collapsed in February 2018 after Firano announced that approximately 17 million Nano tokens — worth roughly $170 million at the time of the announcement — had been stolen from the platform. Firano initially framed the loss as an external hack and demanded that the Nano development team alter the blockchain to reverse the transactions, a demand the team publicly refused. Italian courts subsequently determined that the losses resulted from Firano’s own gross mismanagement, that he had known about early-stage thefts for months before disclosing them, and that he had personally extracted Bitcoin from the exchange in the days immediately before making the loss public. The Florence Bankruptcy Court declared both Bitgrail and Firano personally bankrupt in January 2019, ordered him to repay users to the maximum extent possible from seized personal assets, and authorized the seizure of his property.
The platform had operated since approximately 2016 and became one of the world’s primary venues for trading Nano — then known as RaiBlocks — during the cryptocurrency bull market of late 2017 and early 2018. At the peak of the bull market, Nano was among the most actively discussed alternative cryptocurrencies, and Bitgrail’s position as an early listing venue gave it disproportionate control over the market for a token with a large and passionate community. When the collapse came, approximately 230,000 registered users were affected, though the number with active balances at risk was a subset of that total.
Italian criminal authorities separately investigated Firano’s conduct and alleged he was directly responsible for the hacks, not merely negligent in preventing them. The distinction between criminal fraud and civil mismanagement — one carrying a criminal conviction and the other an obligation to repay — defined the legal proceedings for years. As of mid-2026, Firano had been declared civilly bankrupt and ordered to repay victims; criminal proceedings were initiated but a final criminal conviction and sentence remained to be confirmed through Italian court records for this reporting period.
Mt. Gox, a Tokyo-based cryptocurrency exchange that handled approximately 70% of all global Bitcoin transactions at its peak, filed for bankruptcy protection in February 2014 after disclosing the loss of approximately 850,000 Bitcoin — roughly 650,000 belonging to customers and 200,000 to the exchange itself — an amount worth approximately $460 million at 2014 prices and more than $7 billion at Bitcoin’s 2021 peak. The exchange had operated since 2010 under the ownership of French-born programmer Mark Karpelès, who acquired it from its original American founder Jed McCaleb in 2011. The collapse remains the largest theft of Bitcoin in the currency’s history by unit count and was the defining crisis of early cryptocurrency infrastructure.
Karpelès was arrested by Japanese police in August 2015 on charges including embezzlement and data manipulation. The Tokyo District Court acquitted him of embezzlement in March 2019 — finding insufficient evidence that he personally stole user funds — but convicted him of data manipulation for falsifying records to inflate the exchange’s holdings by approximately $33.5 million. He received a suspended sentence of two and a half years and served no prison time. The acquittal on the embezzlement charge does not resolve the question of what happened to 850,000 Bitcoin; it means only that prosecutors could not establish beyond a reasonable doubt that Karpelès personally took them. The Tokyo High Court upheld the conviction on appeal in 2020.
The recovery process has extended for more than a decade. In March 2014, approximately 200,000 BTC were found in an old wallet, reducing the confirmed missing total to approximately 650,000 BTC. Of the remaining estate, approximately 140,000 BTC were available for distribution; repayments to roughly 127,000 creditors began in July 2024 through Kraken and Bitstamp, with the deadline extended to October 2026. Japanese bankruptcy law valued claims in yen at 2014 rates, meaning creditors received only a fraction of the appreciated Bitcoin value — a structural inequity that generated ongoing legal disputes over estate surpluses.
ACX Exchange, the cryptocurrency trading platform operated by Melbourne-based Blockchain Global Limited under the domain ACX.io (associated with Bitcoin.com.au), collapsed in late 2019 when customers found themselves unable to withdraw funds or cryptocurrency assets. Total unsecured creditor claims lodged with liquidators reached A$58,648,886 as of October 2023, of which A$22,753,442 represented claims from former ACX Exchange customers — a figure regulators describe as likely understating actual user losses given that many affected account holders did not file formal claims. Blockchain Global entered voluntary administration in October 2021 and liquidators were formally appointed on February 11, 2022.
The platform was operated under the direction of co-founders and directors Sam Lee and Liang “Allan” Guo, alongside co-founder Vincent Vu. Liquidator reports filed with ASIC in November 2023 identified potential breaches of the Corporations Act by current and former officeholders. ASIC commenced a formal investigation in January 2024 and filed civil penalty proceedings against Allan Guo in the Federal Court. A further development came on June 3, 2026, when the Federal Court stayed those civil proceedings pending a decision by the Commonwealth Director of Public Prosecutions on whether to lay criminal charges — an indication that the evidentiary threshold for criminal prosecution was under active assessment. As of that date, Guo had departed Australia on September 23, 2024, following the expiry of travel restraint orders, and had not returned.
The roughly 22,000 individuals who filed creditor claims were ordinary Australian retail investors who had deposited cryptocurrency and fiat currency into what presented as a professionally managed exchange. Active since approximately mid-2016 under the Bitcoin.com.au brand, it positioned itself as part of Australia’s legitimate crypto infrastructure. Users who lost funds have received no distribution from the liquidation estate to date.