Hundreds of banks use Fed’s new instant-payment service, but universal availability could remain a long way off. The Fed declined to release data about use of FedNow, which consumers don’t interact with directly. The more than 300 banks it has said are using the platform represent a fraction of the roughly 9k U.S. banks and credit unions. Some are tiptoeing onto the service, allowing customers to receive, but not send, instant payments, according to bank and Fed officials.