SEC says cyber security biggest risk to financial system

By Lisa Lambert and Suzanne Barlyn WASHINGTON (Reuters) - Cyber security is the biggest risk facing the financial system, the chair of the U.S. Securities and Exchange Commission (SEC) said on Tuesday, in one of the frankest assessments yet of the threat to Wall Street from digital attacks. The SEC, which regulates securities markets, has found some major exchanges, dark pools and clearing houses did not have cyber policies in place that matched the sort of risks they faced, SEC Chair Mary Jo Wh