NEW YORK -- For investors, a volatile stock market passed a worrisome milestone on Monday.
The market logged its longest losing streak in two months, and extended a sell-off that began last week.
After biotechnology and internet stocks pulled the market lower on Friday, it was companies that sell non-essential goods and services that dragged on the market to start the week. Concerns about earnings and sales drove declines. CarMax slumped after the used car dealer reported lower net income, and Mattel dropped on concerns about demand for big-name toys.
Stocks have been volatile this year after surging in 2013. Investors now appear to question whether their lofty prices will be justified by what's expected to be slower growth in first-quarter earnings.
"The markets are struggling to choose a direction," said Joe Tanious, a global market strategist for JPMorgan Funds. "I suspect that this choppiness in the markets is something we are going to be seeing for some time to come."
The Standard & Poor's 500 index fell 20.05 points, or 1.1 percent, to 1,845.04. It has fallen for three straight days, the longest losing span since late January, and has shed 2.4 percent since its all-time high of 1,890.89 on April 2.
The Dow Jones industrial average dropped 166.84 points, or 1.02 percent, to 16,245.87 Monday. The Nasdaq composite had the biggest decline, falling 47.97 points, or 1.2 percent, to 4,079.75.
There were signs of stability in the market. Technology and biotechnology stocks, which were pummeled by investors at the end of last week, were mixed on Monday.
Facebook edged up 20 cents, or 0.4 percent, to $56.95 on Monday after it dropped 4.6 percent Friday.
Netflix, which also slumped last week, gained 69 cents, or 0.2 percent, to $338.
Consumer discretionary stocks -- companies that sell goods and services that are not necessities for shoppers -- saw the biggest decline among the S&P 500's 10 sectors.
CarMax slipped $1.88, or 4.1 percent, to $43.68 after the company said late Friday that its fourth-quarter earnings fell. Net income declined as the effects of an accounting correction offset higher demand for its vehicles. The company's revenue also missed Wall Street expectations.
Mattel dropped $1.15, or 2.9 percent, to $38.26 after analysts at BMO Capital cut their outlook for the toy company, citing lower demand for key products such as Barbie dolls and Hot Wheels cars.
Investors will focus more and more on the outlook for corporate earnings this week, as companies begin to announce first-quarter results. Aluminum maker Alcoa, JPMorgan and Wells Fargo are reporting.
Overall, companies in the S&P 500 index are expected to see earnings growth of 0.3 percent over last year's first quarter. That rate of growth, however, is down from 8 percent in the fourth quarter, and would be the lowest since the third quarter 2009, when earnings contracted 1.7 percent, according to S&P Capital IQ.
While the outlook is poor, the low expectations may actually help stocks, because they give companies a lower hurdle to overcome, said Warne.
"The expectations are incredibly low, largely due to the impact of winter weather," said Kate Warne, an investment strategist at Edward Jones.
JPMorgan is expected to report earnings of $1.41 per share for the first quarter on Friday, a decline from earnings of $1.59 per share for the same period a year earlier, according to FactSet data.
Nine of the ten industry groups that make up the S&P 500 index fell Monday. The only sector in the S&P 500 to rise was made up of consumer staples stocks, or companies that sell essential consumer goods. Investors typically buy these stocks when the market slumps.
In government bond trading, the yield on the 10-year Treasury note fell to 2.70 percent from 2.72 percent late Friday. The price of crude oil fell 70 cents, or 0.7 percent, to $100.44 a barrel. Gold fell $5.20, or 0.4 percent, to $1,298.30 an ounce.