The S&P 500 was down 1.2% to 4,142.79 during midday trading.
The Dow Jones Industrial Average fell 0.5% to 33,950.60.
The Nasdaq dropped 2.7% to 13,517.96.
The yield on a 10-year Treasury was down 0.8% to 1.6%.
The price of gold decreased 0.9% to $1,775.10.
The price for a barrel of oil rose 1.8% to $65.66.
Newport Beach-based Clean Energy Fuels Corp. (Nasdaq: CLNE) shares fell 5.4% to $10.45 apiece for a market cap of $2.1 billion. Zacks Equity Research said: “Our proven model does not conclusively predict an earnings beat for Clean Energy this time around.” The company is scheduled to release first-quarter earnings on Thursday.
Shares in STAAR Surgical Company (Nasdaq: STAA) in Lake Forest fell 10% to $124.98 apiece for a market cap of $5.8 billion. Zacks Equity Research said investors expect a year-over-year decline in earnings on higher revenues when Staar reports quarterly earnings tomorrow.