Oil drop stymies Dow's march to 20,000; health stocks boost Nasdaq

The Nasdaq notched a record high close, extending its bullish run with help from healthcare stocks. The S&P's energy sector dropped 1.5 percent as oil prices slid on concerns that rising Iraqi exports and U.S. output could dampen the impact of a deal among major producers to limit output. The S&P 500 benchmark has risen more than 6 percent since the Nov. 8 election of Donald Trump, who has pledged tax cuts, lighter regulation and fiscal stimulus, but investors are now waiting to see if h