For about four hours Wednesday, Federal Reserve systems that execute millions of financial transactions a day—everything from payroll to tax refunds to interbank transfers—were disrupted by what appeared to be some sort of internal glitch.

Systems were mostly restored by the end of the day, but the outages once again beg questions about the resilience of critical infrastructure that Americans rely on to process payments. The episode follows two significant disruptions to the Fed's payment services that occurred in 2019.

"It does raise awareness about what their business continuity measures are and what's going on over a single point of failure that doesn't have a lot of redundancies. It's pretty concerning," said David Hart, president of consulting firm NETBankAudit who was previously a senior bank examiner and IT auditor at the Richmond Fed.