Dow Jones closed at an all-time high for a ninth straight session, the longest streak since January 1987.
The Dow Jones Industrial Average rose 32.6 points or 0.16 percent to 20,775.6.
It was buoyed by a 3-4 percent gain in DuPont shares. The company is set to win antitrust approval from European Union regulators for its $130 billion merger with Dow Chemical. Dow Chemical shares rose 4 percent.
A solid corporate earnings season has also encouraged investors. Profits for S&P 500 companies are on track to rise 7.6 percent in the fourth quarter, the best quarterly growth since the third quarter of 2014.
Toll Brothers shares rose 6.1 percent after the luxury homebuilder reported higher-than-expected quarterly profit and revenue.
The S&P 500 lost 2.56 points or 0.11 percent to 2,362.82 and the Nasdaq Composite dropped 5.32 points or 0.09 percent to 5,860.63.
The S&P energy sector fell 1.6 percent as oil prices dropped.
Declining issues outnumbered advancing ones on thes NYSE by a 1.27-to-1 ratio; on Nasdaq, a 1.51-to-1 ratio favored decliners.
The S&P 500 posted 57 new 52-week highs and one new low; the Nasdaq Composite recorded 143 new highs and 31 new lows.
About 6.5 billion shares changed hands in U.S. exchanges, below the 6.8 billion daily average over the last 20 sessions.
The risks facing the U.S. economy are more in balance, allowing the Fed to gradually raise interest rates, said Gov. Jerome Powell to the Forecaster’s Club of New York.
Meanwhile, some analysts warned that the rally on Wall Street and overly complacent attitude among investors are creating a dangerous situation.
“Make no mistake, lowering taxes is truly pro-growth and will keep the strong undertone of growth moving ahead. This will, however, mean a tighter monetary policy. Although we recognize that rates are below normal, the fact is that when the tightening process begins, the ‘full speed ahead’ of climbing stocks will run into a brick wall,” said Peter Cardillo, chief market economist at First Standard Financial, in emailed notes.