Midday Report: Apple's iPhone 7 Preorders Surge; U.S. Stocks Tumble

Stock losses escalated as a relief rally seen a day earlier faded. Oil was also a major drag after the International Energy Agency forecast a slowdown in global growth demand. Weight Watchers  (WTW) - Get Report  slid after CEO James Chambers announced his resignation. The board established a committee that includes Oprah Winfrey to search for a replacement. Winfrey has been involved since last October after purchasing a stake in the company. Apple  (AAPL) - Get Report rose after suppliers T-Mobile  (TMUS) - Get Report and Sprint  (S) - Get Report reported strong preorders for the iPhone 7 and iPhone 7 Plus. Sprint said orders for the latest models were up more than 375% over the first three days compared to last year. Chevron (CVX) - Get Report was rated new outperform at BMO Capital. The firm said the oiler is at an inflection point and can deliver higher-margin growth. TheStreet's Keris Lahiff reports from Wall Street.