By Matthew Miller BEIJING (Reuters) – Domestic authorities in European Union member states should stress-test their financial institutions for cyber risks, a top E.U. supervisor said, warning banks might be required to hold extra capital as a buffer against what is an emerging threat. Speaking to Reuters in Beijing on Friday, Andrea Enria, chairman of the European Banking Authority (EBA), said cyber security had become an important issue for E.U. member states. "But if you ask me would I recommend competent authorities to think more on this and consider running this type of stress test?