(Reuters) - U.S. stocks were set to open lower on Wednesday, halting a four-day run of gains after the United States threatened to impose tariffs on an additional $200 billion worth of Chinese goods, dampening hopes of a compromise on trade. U.S. officials on Tuesday issued a list of thousands of Chinese imports that the Trump administration wants to target with new tariffs, including hundreds of food products, as well as tobacco, chemicals, coal, steel and aluminum.
