REvil has risen among ransomware gangs, some experts say, with standout audaciousness and even dramatic flair.

REvil, also called Sodinokibi, is an infamous hacking group perhaps best known for launching digital extortion attacks against Apple.

This could spell trouble for victims trying to avoid paying out ransoms.

It's all about economics.

These figures come as insurers continue to assess whether to pay the extortion fees that hackers impose on their clients.

Whether the currency-exchange company paid the ransom remains unclear.