The S&P 500 was down 0.8% at 4,129.79 during midday trading.
The Dow Jones Industrial Average fell 0.7% to 33,828.23.
The Nasdaq decreased 1.1% to 13,761.50.
The yield on a 10-year Treasury bond dropped 2.4% to 1.562%.
The price of gold increased 0.5% to $1,779.20.
The price for a barrel of oil fell 1.6% to $62.37.
Clean Energy Fuels Corp. (Nasdaq: CLNE) in Newport Beach fell 18% to $9.70 per share for a market cap of $1.9 billion, the day after shares surged on news of a deal with Amazon (Nasdaq: AMZN). Yahoo! quoted Raymond James analyst Pavel Molchanov as saying in a note to clients that investors have gotten "carried away by headlines over substance" while he downgraded the stock to underperform.
Alignment Healthcare Inc. (Nasdaq: ALHC), an Orange-based provider of Medicare Advantage insurance plans, dropped 7.6% to $23.22 per share for a market cap of $4.4 billion. Despite today’s decrease, the stock is still up about 20% since the company’s initial public offering at the end of last month.