Zelle is seeing thousands of signups each day and last year saw $75bn in payments, but fraud has become a bigger problem for the company; fraudsters have used some weaknesses like inconsistent notifications when money is sent or received and the speed of transactions because the full posting happens later; they have also seen spoof emails or texts which trick customers into authorizing transactions to a fraudster, Zelle and the banks say they are working on improving the issues. Source.
