According to a report published by Akamai, the DD4BC criminal group has been responsible for at least 114 DDoS attacks on its customers since April 2015. The group attempted to extort money from financial companies and other business by threatening to hit them with DDoS. The criminals request their victims the payment of a specific ransom amount in Bitcoins to stop the DDoS attack. In one case, the attack flooded the target with over 56.2 Gbps of traffic, in June the group ran at least 8 attacks that had peak bandwidths of more than 23 Gbps.”]
Source: https://securityaffairs.co/wordpress/40034/cyber-crime/dd4bc-group-extortion-ddos.html