According to the report released Monday, investment fraud was the most widespread — and most expensive — type of crypto-related fraud in 2023. Of the more than 69,000 reports of crypto-related crime the agency received last year, nearly half were reports of investment fraud, with investment fraudsters making off with as much as $4 billion. And while cryptocurrency crime only made up about 10% of the complaints the FBI received, the $5.6 billion was about half of the total losses suffered by complainants.