The operators of the REvil Ransomware, otherwise known as Sodinokibi, have announced that they will use stolen files and data as leverage to get victims to pay ransoms. They claim that a recent operation from this group is the attack against the CyrusOne data center that was reported last week. If a company does not pay the ransom, the ransomware actors will publicly release the stolen data or sell it to competitors. It is in their opinion that this would be more costly to the victim than paying the ransom.
Source: https://www.bleepingcomputer.com/news/security/another-ransomware-will-now-publish-victims-data-if-not-paid/