US STOCKS-The S&P 500 has worst day since October as virus fears mount By: Reuters: Company News January 24, 2020 at 16:25 PM EST * Indexes drop: Dow 0.58%, S&P 0.90%, Nasdaq 0.93% (Updates to market close) Read More >> Related Stocks: Amazon.com American Express Apple Boeing Co Broadcom Ltd Caterpillar Facebook Intel Corp McDonald's Corp Qorvo Inc Skyworks Solutions Starbucks Corp Tesla, Inc.