U.S. Stocks Open Lower, Eye Weekly Loss

U.S. stocks opened lower on Friday as news of regulatory changes from China sent shock waves across global equity markets. The main indexes were on track to record a weekly loss after two consecutive weeks of gains. After Asia's market closed for trading China's securities regulator announced new rules, tightening margin lending while the country's two stock exchanges said they would make it easier to short sell stocks in an effort to rein in country's soaring stock markets. The S&P 500 opened 12 points, or 0.6%, lower at 2,093. The Dow Jones Industrial Average dropped 146 points, or 0.8%, to 17,960. The Nasdaq Composite began the session down 34 points, or 0.7%, to 4,972.