NEW YORK (AP) -- U.S. stocks are down again Monday and the S&P 500 is trading near its lowest levels this year as health care stocks stumble. Health insurers and hospitals are falling after a judge in Texas ruled that the 2010 Affordable Care Act is unconstitutional. Retailers and technology companies are also sinking.
KEEPING SCORE: The S&P 500 shed 13 points, or 0.5 percent, to 2,586 at 10:15 a.m. Eastern time. The benchmark index is trading around its lowest levels this year, which it set during a big drop in early February. The Dow Jones Industrial Average lost 132 points, or 0.6 percent, to 23,968. The Nasdaq composite fell 32 points, or 0.5 percent, to 6,878. The Russell 2000 index gave up 9 points, or 0.7 percent, to 1,401.
The Russell 2000 has fallen almost 20 percent since it finished at its last record high at the end of August. Wall Street calls a 20 percent decline a "bear market," and it's considered a major downturn.
The S&P Small Cap 600 index went into a bear market Friday as investors continue to lose confidence in the U.S. economy's growth prospects. Smaller companies are considered more vulnerable in a downturn than larger companies because they are more dependent on economic growth and tend to have higher levels of debt.
HEALTH SCARE: Hospital operator HCA dropped 4.2 percent to $121.37 while health insurer UnitedHealth lost 2.4 percent to $258.60. Centene, a health insurer that focuses on Medicaid and the Affordable Care Act's individual health insurance exchanges, fell 7.6 percent to $117.96 and Molina skidded 14.8 percent to $112.18.
Many experts expect the ruling will be overturned, but with the markets suffering steep declines in recent months, investors didn't appear willing to wait and see.
TRADE TENSIONS: China and the United States clashed again over their respective trade policies Monday, as China criticized what it calls a "unilateralist and protectionist" approach to trade. The U.S. ambassador to the World Trade Organization said those critiques were unwarranted. The two nations have been embroiled in a dispute over technology policy and other issues for most of this year. With no end to the conflict in sight, investors are growing more concerned that the tensions will drag down the already-slowing global economy.
BONDS: Bond prices rose. The yield on the 10-year Treasury note fell to 2.87 percent from 2.89 percent.
The Federal Reserve is expected to raise interest rates again Wednesday, the fourth increase of this year. It's been raising rates since over the last three years, and investors will want to know if the Fed is scaling back its plans for further increases based on the turmoil in the stock market over the last few months and mounting evidence that world economic growth is slowing down.
UK QUESTIONS: British Prime Minister Theresa May was set to reject the idea of another referendum on Britain's departure from the European Union Monday. Britain is scheduled to leave the EU in late March, and legislators don't support a set of rules agreed to by May and European Union leaders. However if Britain leaves without a deal, it could bring huge disruptions to the British and European economies and financial markets.
OVERSEAS: Germany's DAX lost 1.4 percent. That means the DAX, which represents Europe's largest single economy, is also in bear market territory. France's CAC 40 fell 1.3 percent and the British FTSE 100 lost 1.1 percent.
Japan's Nikkei 225 index added 0.6 percent and the Kospi in South Korea gained 0.1 percent. Hong Kong's Hang Seng was less than 0.1 percent lower. Both the Kospi and Hang Seng are in bear markets as well.
ENERGY: Benchmark U.S. crude fell 1.1 percent to $50.66 a barrel in New York. Brent crude, used to price international oils, added 0.4 percent to $60.50 a barrel in London.
CURRENCIES: The dollar fell to 112.93 yen from 113.29 yen. The euro rose to $1.1333 from $1.1303. The British pound climbed to $1.2609 from $1.2579.
AP Markets Writer Marley Jay can be reached at http://twitter.com/…