Dow Industrials Fall More Than 500 Points

U.S. stocks fell sharply Wednesday, extending their turbulent run as hopes for additional fiscal stimulus dimmed, coronavirus cases rose and investors continued to question the valuations of tech stocks.

Stocks have whipsawed this week: the S&P 500 briefly neared correction territory Monday—defined as a retreat of 10% from a recent high—only to rebound Tuesday. One bright spot on both days was the technology sector, which showed signs of stabilizing after dragging down indexes in previous weeks.

But…