The report, which looks at criminal activity and money laundering in the digital currency market, also showed a steadily growing number of smaller thefts in the $20-60 million range, totaling $173 million in the third quarter.

Digital currencies stolen from exchanges in 2017 totaled just $266 million, according to a previous report from CipherTrace.

Bitcoin’s popularity and the emergence of more than 1,600 other digital coins or tokens have drawn more hackers into the cryptocurrency space, expanding opportunities for crime and fraud.

“The regulators are still a couple of years behind because there are only a few countries that have really applied strong anti-money laundering laws,” Dave Jevans, chief executive officer of CipherTrace, told Reuters in an interview.

Jevans is also the chairman of the Anti-Phishing Working Group, a global organization that aims to help solve cyber crime.

He said there are likely 50 percent more criminal transactions than those that were traced for this report. For instance, CipherTrace is aware of more than $60 million in cryptocurrency that was stolen but not reported.

The data also showed that the world’s top cryptocurrency exchanges from countries with weak anti-money laundering regulations (AML) have been used to launder $2.5 billion worth of bitcoins since 2009. The top 20 virtual currency exchanges in terms of volume were analyzed for the report.

The CipherTrace report declined to name those exchanges.

These money-laundered funds represent transactions that CipherTrace was able to directly monitor and designate as criminal or highly suspect.

In estimating the $2.5 billion, CipherTrace looked at about 350 million transactions from the 20 exchanges and found 100 million of those with counterparties. From there, the firm was able to cross-check the 100 million transactions with its own data on criminal activity.

At the same time, these exchanges have also been used to purchase 236,979 bitcoins worth of criminal services, equivalent to approximately $1.5 billion at current prices, the report showed.

“All exchanges get these money-laundered funds. You really can’t stop them,” said Jevans.

“And here’s the reason why. We learn about the criminal stuff often times after it actually happened. So there’s no way to know in real time. You can know 80-90 percent of the time, but it’s impossible to know 100 percent,” he added.