The S&P 500 was down 0.8% in midday trading to 2,064.27.
The Dow Jones Industrial Average was down 0.7% to 17,766.55
The NASDAQ was down 0.9% to 4,774.90.
The yield on a 10-year Treasury bond was down 3.7% to 1.80%.
The price of gold was down 0.6% to $1,288.
Irvine-based Western Digital Corp. was down 4% to $39.25 and a $9.1 billion market cap. The memory products maker’s shares have fallen 16% since Friday, when it said it would borrow $9.9 billion to help pay for its SanDisk Corp. acquisition.
Lake Forest-based Del Taco Restaurants Inc. was up 5% to $9.45 and a $365 million market cap. The fast food chain reported a profit for the first quarter of 2016 compared with a loss in the same period last year.
Orange County homebuilders declined in a down market and as the companies report quarterly results. CalAtlantic Group Inc. and Tri Pointe Group Inc., both in Irvine, were each down about 2.5%. Newport Beach-based William Lyon Homes and Aliso Viejo-based New Home Co. Inc. were each down about 4.5%.
New Home Co. and Tri Pointe reported results last week; CalAtlantic Group is scheduled to report Thursday and William Lyon Homes is set to report results Monday.
Irvine-based Autobytel Inc. was down 6.5% to $15.13 and a $161 million market cap. The automobile sales leads provider had traded shares by midday at a rate about 50% higher than its 90-day average.