Since EWS (The company that runs zelle) is effectively co-owned by a bunch of the large banks in the US, which has caused many of the small and mid-sized banks

Since EWS (The company that runs zelle) is effectively co-owned by a bunch of the large banks in the US, which has caused many of the small and mid-sized banks don't want to take part. They worry transaction information and the size of their bank (based on traffic) when leak its way to the large banks giving them some kind of advantage.