OneCoin
OneCoin is one of the major pyramid schemes in the crypto sector: it was active from 2014 to 2017, having stolen about 5 billion dollars from three million investors. The founder of OneCoin isRuzha Ignatova, a Bulgarian-born criminal. The scam took the form of the classic Ponzi scheme: participants received a reward for each new participant they invited.
Ignatova promised that OneCoin would soon become the most important cryptocurrency in the world, and that it would even "get Bitcoin out of the way", but this currency did not even have its own blockchain and was accepted as a means of payment only on the sites associated with the scheme.
The Bulgarian government publicly warned citizens of OneCoin-related risks, as it was not a financial instrument controlled by public regulators. But this did not hinder the expansion of the pyramid scheme, which also expanded abroad.
Shortly afterwards, the governments of the United Kingdom, Austria and Thailand also advised citizens not to participate in the operation. Italy and Germany even went so far as to prohibit OneCoin's activities and blocked accounts. Ignatova did not appear at the investor meeting he had planned in Lisbon, and his tracks have been lost since then.
The U.S. government has accused Ruzha Ignatova of fraud and money laundering: she now faces 25 years in prison, while some of her accomplices have already been brought to justice, such as her lawyer, brother and former business partner.