The Dow Industrial Average further tumbled following the arrest of the C.F.O. of the major Chinese tech firm. Falling more than 400 points as the markets opened Thursday, tech-heavy Nasdaq joined the slide down, dropping 1.9 percent within correction area, which begins when there is a 10 percent or more drop from the high. Standard & Poor 500 Index is also 1.7 percent away from broaching correction territory. Brief optimism following the recent G20 summit has turned into uncertainty over future U.S. China trade negotiations impacting markets.