Stocks rose on Friday, the first day of March, as investors built on the market's strongest start to a year in nearly three decades.
The ended the day up 0.7 percent at 2,803.69, closing above 2,800 for the first time since Nov. 8. The Dow Jones Industrial Average closed 110.32 points higher at 26,026.32 as Nike and Chevron outperformed. The Nasdaq Composite advanced 0.8 percent to 7,595.35, led by gains in Amazon.
The S&P 500 traded around the key 2,800 level for most of this week, briefly breaking above it on Monday and Tuesday on an intraday basis.
"We know how prominent the 2,800 level has been, and it goes way beyond the last few days," Frank Cappelleri, executive director at Instinet, wrote in a note. "In fact, this now is the 11th visit to the 2,800 zone since the start of 2018."
"As we saw last summer, once 2,800 was officially overtaken, it became support. And that support helped propel the market to new highs," he said.
Friday's moves come a day after the major indexes posted solid monthly gains in February, pushing the S&P 500 to its best start to a year since 1991. The S&P 500 is up more than 11 percent for the year, along with the Dow. The Nasdaq, meanwhile, is up more than 14 percent.
This could mean further gains for investors as the year goes on. Data compiled by LPL Financial show that, in 25 of 27 occasions since 1950, the S&P 500 has posted gains in the final 10 months after rising in January and February.
"We think equities have some room to go higher," said Jeroen Blokland, a portfolio manager at Robeco. But "I don't think we get another rally like that. It's going to be a little bit more difficult. It could happen, but a lot of things would have to go right."
Decreasing trade tensions between China and the U.S., along with declining fears of tighter monetary policy from the Federal Reserve, helped propel stocks higher to kick off 2019.
Bloomberg News reported Thursday that U.S. officials are getting a final trade deal ready for President Donald Trump and Chinese President Xi Jinping to sign around mid-March.
That report came after White House economic advisor Larry Kudlow told CNBC the two countries are making "fantastic" progress in their negotiations. Treasury Secretary Steven Mnuchin also told CNBC the two sides have "made a lot of progress."
Stocks came off their highs on Friday following the release of disappointing economic data. The Institute for Supply Management released data showing U.S. manufacturing activity expanded at its slowest pace since November 2016. Meanwhile, the University of Michigan consumer sentiment index came in below expectations for February. The Atlanta Federal Reserve's GDPNow model also showed an estimate of 0.3 percent for first-quarter GDP.
Shares of Tesla dropped more than 7 percent after CEO Elon Musk said the company would not turn a profit for the first quarter. Tesla launched its standard Model 3 car, which starts at $35,000. However, analysts were unimpressed by the announcement. A Barclays analyst even called it the "un-iPhone moment."
Amazon shares rose nearly 2 percent after The Wall Street Journal reported the company had plans to open its own grocery store chain at a lower price point than Whole Foods. Shares of Kroger took a beating on the news, sliding more than 4 percent.
—CNBC's Sam Meredith contributed to this report.