Blockchain analysis firm Chainalysis has revealed new data that suggests that two cyber-criminal rings could be responsible for the majority of cryptocurrency stolen in recent years.

While there are dozens of hacker groups across the globe, and many more individual hackers working in solitary, two specific groups are said to be responsible for as much as $1 billion in stolen cryptocurrencies, according to a new report featured in the Wall Street Journal.

New research from Chainalysis claims that two groups, only referred to as Alpha and Beta, are responsible for an overwhelming majority of all cryptocurrencies stolen as part of scams. These scams often include phishing attacks, Twitter giveaway schemes, and much more.

The hackers make a tremendous effort to hide their activities, often transferring crypto roughly 5,000 times before finally converting the stolen funds to cash via cryptocurrency exchanges. One group, according to blockchain analysis, begins transferring funds immediately, while the other group is more calculated in their approach, oftentimes waiting as much as 18 months before taking steps to transfer the funds.

Furthermore, Chainalysis suggests that one group is a “heavily sanctioned organization heavily focused on the money,” while the other is a “giant, tightly controlled organization at least partly driven by non-monetary goals.” The firm didn’t speculate on what the non-monetary goals might be, but one would have to assume that there would be at least some monetary interest to be dealing in digital currencies.

Because the funds are transferred around so much, tracing the stolen funds can be difficult, and the funds often squeak through exchanges with Anti-Money Laundering systems.

In 2018, cryptocurrency related theft broke all previous records, and 2019 is already off to another strong start. In January alone, the New Zealand-based cryptocurrency exchange Cryptopia was hacked, and over the weekend, LocalBitcoins users were targeted in a phishing attack.