@gudenau @mathew AFAIK, this is a vulnerability particular to proof-of-stake currencies. They're meant to replace computation intensive proof-of-work schemes by giving verification powers to the largest stakeholders. That's how this transaction happened: The trader in question borrowed enough to become the largest single stakeholder in the system, which gave them unilateral powers to verify their own transaction. It's a known vulnerability that PoS schemes struggle to defend against.