Top 5 Biggest Crypto Scams In History

Cryptocurrencies are, without doubt, the hottest financial market in the world right now. Renowned for its innovative approach, and spearheaded by the revolutionary blockchain-based, decentralized ledger technology, and peer-to-peer, non-intermediary transactions.

Despite its prowess, the industry can’t help to shake off concerns related to scams, and deservedly so. Scams have been synonymous with cryptocurrencies ever since we first began hearing about them, and their threat cannot be ignored because of the impact they have on undermining trust, even driving calls for increased regulation of the asset class.

In this article, we will look back at some of the largest crypto-related frauds in history, touching upon their methods and the long-term consequences for the broader industry.

5 Biggest Crypto Scams in History

1. Mt. Gox: $40+ Billion (Estimated Loss)

Japanese cryptocurrency exchange Mt. Gox was among the first digital asset trading platforms to ever exist, and during its peak, the Bitcoin-only exchange handled 70% of all BTC trades. However, concerns began to rise after it suspiciously suspended withdrawals citing technical issues in 2014, which alerted authorities.

An investigation found that Mt. Gox had suffered an exploit that led to about 850,000 BTC, worth over $450 million at the time, being stolen. The hack stemmed from poor internal security measures and years of mismanagement. Mark Karpele, founder and CEO of the exchange, declared bankruptcy soon after and was sentenced to prison. Unfortunately, Mt. Gox’s customers never got their Bitcoins back. The loot led to Japan formalizing crypto exchange regulations under its Financial Services Agency (FCA), one of the earliest adopters of crypto-focused compliance standards. The stolen coins are worth upwards of $40 billion today.

2. FTX Exchange: $8-10 Billion (Estimated Loss)

FTX was the third-largest cryptocurrency exchange by trading volume, driving users from all over the world through its celebrity endorsements and sports team partnerships. Its founder, Sam Bankman-Fried, was even featured on Forbes Magazine as the youngest crypto billionaire. However, things came crashing down in late 2022 after a bombshell article by CoinDesk revealed under-the-table dealings between FTX and its sister-company, Alameda Research. 

FTX was apparently moving customer funds to the market maker and investment firm, which was presumed to be one of its institutional clients, to make investments outside of its business and pay off liabilities. Around $10 billion in customer funds went missing, triggering one of the biggest bear markets in crypto history. Bankman-Fried was arrested in the Bahamas in December 2023 and is currently serving time in a US prison. The FTX crash led to a significant crackdown on crypto firms in the United States, with regulators imposing stricter governance on trading platforms.

3. OneCoin: $4.4 Billion (Estimated Loss)

The OneCoin scam has been crowned as the king of all crypto scams. The pyramid scheme run by a woman named Ruja Ignatova managed to attract billions of dollars in investments from investors in 175 countries on the promise of creating a cryptocurrency called OneCoin, claiming that it had the potential to topple the alpha cryptocurrency – Bitcoin (BTC)

She, alongside her husband, sold educational packages and other rewards while enticing users into a multi-level marketing scam, which never delivered on its “revolutionary” blockchain technology. In 2017, their scam came to light after the project collapsed and the founders embezzled an estimated $4.4 billion or more. Ignatova’s husband and other core members of OneCoin were arrested, with the Interpol putting out a wanted notice for the self-proclaimed “Crypto Queen”. After being on the run for more than five years, she was finally arrested in 2023 and is facing 20 years in prison.

4. Thodex: $2+ Billion (Estimated Loss)

Thodex was a Turkish cryptocurrency exchange founded by Faruk Fatih Ozer in 2017. He attracted investors to deposit their digital assets on the platform by promising them free Dogecoin (DOGE), which resulted in a pool of $2.2 billion.

In early 2021, the platform shut down for a scheduled 6-hour maintenance, which was later extended to five days. Following customer complaints, law enforcement officials led an investigation, which found that the founder had shut down the exchange and made away with billions in user funds. He has never been found. The event led Turkish authorities to introduce emergency measures to mitigate crypto scams by enforcing strict regulations.

5. PlusToken: $2+ Billion (Estimated Loss)

PlusToken is a crypto Ponzi scheme that operated from China as a high-yielding cryptocurrency wallet that promised up to 30% returns on deposits. What was happening behind the scenes was the company pooling funds from newer investors to pay earlier investors in a classic Ponzi structure.

The operation met its end in 2019, when the founders swindled millions of dollars before disappearing with over 180,000 BTC and 6 million ETH, and other tokens, which are valued upwards of $2 billion as of 2025. China’s response to the PlusToken scam was swift, intensifying the crackdown on crypto-related activities and completely banning their use. PlusToken became a global case study in crypto anti-money laundering (AML) practices cited by the Financial Action Task Force (FATF).

What is a Crypto Scam?

Crypto scams are fraudulent operations run by bad actors who use various malicious means to steal digital assets from unsuspecting investors. They come in all shapes and sizes, from phishing scams to rug pulls, Ponzi schemes, fake wallets and exchanges, blackmail, fake jobs, investment scams, and more.

Most scams can be narrowed down to one of two forms:

• Activities that encourage victims to willingly transfer their crypto to malicious actors. Main examples of this type are romance scams, false or fraudulent business or investment opportunities, and address poisoning scams.

• Deceitful or fraudulent schemes where the scammers try to get access to their victims’ wallets through phishing schemes, which involve fake trading or airdrop platforms.

How to Identify a Crypto Scam?

Here are some ways to stay safe when dealing with cryptocurrencies by spotting potential scams:

• Always read a project’s whitepaper before investing. Allocate time to look through the whitepapers of blockchains, tokens, or trading platforms to learn about their utility, and check whether they are credible. If the whitepaper does not provide clarity, then it is safe to assume that the project may be fraudulent.
• Be mindful of emails or messages that you receive from crypto exchanges or wallets, as sometimes, bad actors can impersonate authentic platforms to send you malicious links that ask you to provide your seed phrase or private keys. No credible project will ask for your private keys through email.
• If any crypto project promises unreasonably high amounts of profit on deposits or investments in a rather short time, then chances are that they are fraudulent. Legit protocols understand that crypto takes a while to generate considerable yields, and it is a volatile market, so no ROI can be guaranteed.
• If a project is indulged in excessive marketing, with no fundamentals to back it, then it is probably a scam. Legit crypto projects are more likely to market through strategic partnerships and increased utility.

Final Thoughts

The fraudulent platforms mentioned in this article stole nearly $30 billion in crypto from their customers, who had entrusted them with their digital asset holdings. These events shed light on why self-custodying your crypto and using credible, regularly audited platforms to buy, sell, and trade tokens is of utmost importance. These are the top 5 crypto scams in history.

Follow the tips mentioned in this article to spot a potential scam and safeguard your cryptocurrencies. As a general rule of thumb, always do your research and seek expert advice before making any crypto-related investment decision.