- The S&P 500 and Nasdaq Composite both fall 0.2 percent, while the Dow Jones Industrial Average dips 12 points.
- Last week, the U.S. and Canada failed to secure an agreement to replace the current NAFTA pact by last Friday's deadline.
- Meanwhile, a Bloomberg report last week suggested that the U.S. administration was on standby to inflict additional levies on $200 billion worth of Chinese goods as soon as this week.
- "When you have that kind of rhetoric at the same time you have a murky month for the market, this is what happens," says Peter Cardillo of Spartan Capital Securities.
Stocks fell on Tuesday as trade tensions between the U.S. and key partners increased to start off the one of the toughest parts of the year for equity investors.
The pulled back 0.2 percent to close at 2,896.72 with telecom and real estate lagging. The Nasdaq Composite dipped 0.2 percent to 8,091.25, led by a decline in Facebook shares, which counterbalanced a gain in Amazon that made it the second U.S.-company to reach $1 trillion in market cap. The Dow Jones Industrial Average slipped 12.34 points to 25,952.48 as Nike and Verizon lagged.
Last week, the U.S. and Canada failed to secure an agreement to replace the current NAFTA pact by last Friday's deadline. While a deal has been arranged with Mexico, President Donald Trump tweeted over the weekend that there was "no political necessity to keep Canada in the new NAFTA deal."
Trump added that Congress shouldn't intervene in the talks, and claimed that if it did, he would "simply terminate NAFTA entirely." Trade talks with Canada are however expected to reignite this week.
Meanwhile, a Bloomberg report last week suggested that the U.S. administration was on standby to inflict additional levies on $200 billion worth of Chinese goods as soon as this week. In an interview with the same media outlet, Trump warned that he would consider removing the U.S. from the World Trade Organization (WTO) if it doesn't "shape up."
The Dow fell as much as 158.87 points before paring losses. The S&P 500 and Nasdaq declined as much as 0.6 percent and 0.8 percent, respectively.
"When you have that kind of rhetoric at the same time you have a murky month for the market, this is what happens," said Peter Cardillo, chief market economist at Spartan Capital Securities.
Shares of trade-sensitive Caterpillar dropped nearly 0.7 percent.
European equities fell broadly as well. The Stoxx 600 index dropped 0.7 percent while the German Dax pulled back 1 percent. Asian stocks were mixed, however, as Chinese markets rose while Japanese shares slipped.
Investors also kept an eye on emerging markets as they get pressured by rising trade fears and a strong dollar. In Turkey, the lira has lost at least 40 percent of its value in 2018 over concerns surrounding President Recep Erdogan's policies and the economy. Meanwhile, the Argentinian government asked the International Monetary Fund (IMF) for an early release of funds from the nation's $50 billion standby financing deal last week — a move that surprised markets and put the peso under pressure.
The U.S. dollar rose 0.4 percent to 95.48 against a basket of currencies. The iShares MSCI Emerging Markets exchange-traded fund (EEM) dropped 2 percent.
Stocks are coming off their best August performance in more than four years as the S&P 500 and Nasdaq both reached all-time highs. The Dow, meanwhile, entered September just 2.5 percent below its record high.
"We may have overextended a little bit" to the upside, said John Augustine, chief investment officer at Huntington Private Bank. "We could see a modest pullback in the next couple of months."
"Moving about 7 percent to the upside in the summer before mid-term elections is unusual," Augustine said. He also noted some of the risks investors face include the sharp declines in emerging markets as well as weakness in housing and autos data.
September has historically been a tough part of the year for investors. Since 1950, September has been the worst month for the Dow and the broader S&P 500, according data from "Stock Trader's Almanac." The Dow averages a decline of 0.7 percent, while the S&P 500 falls 0.5 percent on average in September, the data show. The Nasdaq, which was introduced in 1971, falls half a percent on average.
Losses in September for the Dow and Nasdaq widen in mid-term election years, while the S&P 500's average decline narrows slightly in such years, according to the data.
Facebook shares dropped 2.6 percent after analysts at MoffettNathanson downgraded them to neutral from buy. The analysts cited a "toxic brew" of slowing sales growth and regulation risk.
Nike's stock fell 3.2 percent amid backlash over a campaign featuring Colin Kaepernick, a former San Francisco 49ers quarterback. Kaepernick has been a polarizing figure since 2016, when he decided to kneel during the national anthem as a protest to racial injustice.
Dow-member Verizon dropped more than 2 percent after analysts at Barclays downgraded them to equal weight from overweight. The analysts pointed to the stock's high valuation, with caps "upside potential."
Amazon shares rose as much as 1.9 percent, briefly pushing the company's market cap to $1 trillion. The milestone comes about a month after Apple, another tech giant, became the first U.S. publicly traded company to reach $1 trillion in market cap.
The ISM U.S. manufacturing PMI rose to 61.3 in August from 58.1 in July. Economists polled by Reuters expected the index to fall to 57.7. The overall PMI got a boost from a sharp jump in new orders.