A system for determining whether a velocity event is fake or real is provided. The system accesses a data store of velocity events, each of which specifies a pair of addresses that share the velocity event. For each address of the velocity events, the system sets a score for that address based on the number of addresses that share a velocity event with that address. When the score for that address satisfies an originating address criterion, the system designates that address as an originating address. The system may determine that a velocity event is real when both addresses of the velocity event are originating addresses.