The DoppelPaymer Ransomware is the latest family threatening to sell or publish a victim’s stolen files if they do not pay a ransom demand. Maze Ransomeware has shown that doing so will increase the number of payments. Doppelpaymer claims to have anonymously sold stolen files on the darknet in the past when a victim chose not to pay the ransom. Maze and Nemty have also started using the same tactic. DoppPaymer is an offshoot of the BitPaymer ransomware.
Source: https://www.bleepingcomputer.com/news/security/doppelpaymer-ransomware-sells-victims-data-on-darknet-if-not-paid/