All 29 of the Dow Jones Industrial Average DJIA, +0.99% components trading in the premarket are declining, as growing worries of a trade war with China has sent Dow futures YMM8, -0.87% tumbling. Only DowDuPont Inc.'s stock DWDP, +2.75% is still inactive ahead of the open. Among the biggest decliners, shares of Boeing Co. BA, +2.74% dropped 2.2%, Merck & Co. MRK, -0.02% shed 2.1% and Caterpillar Inc. CAT, +2.03% dropped 1.4%. The most-active stock is Apple Inc.'s AAPL, +0.69% which fell 1.4%. Dow futures shed 269 points.