Stock futures tumbled Sunday night to kick off a new trading month as investors weighed new U.S. tariffs on goods from key trade partners and their potential impact on the economy and corporate profits.

Futures tied to the Dow Jones Industrial Average slid 528 points, or 101%. S&P futures dropped 1.9%, while Nasdaq-100 futures lost 2.7%.

President Donald Trump on Saturday slapped a 25% tariff on goods from Mexico and Canada. He also placed a 10% levy on imports from China. The U.S. does about $1.6 trillion in business with the three countries.

Canada responded with retaliatory tariffs of its own, while Mexico said it would explore levies on U.S. imports. The Chinese government, meanwhile, said it would file a lawsuit with the World Trade Organization.

“Markets may now need to take the rest of Trump’s tariff agenda literally rather than just seriously … If this new level of seriousness gets priced in suddenly, Monday could be a rough day for markets,” Wolfe Research head of U.S. policy and politics Tobin Marcus said in a note.

Traders are also looking ahead to the biggest week for fourth-quarter earnings, which have become increasingly important in determining the state of the market as tariff concerns ramp and artificial intelligence stocks remain under scrutiny. More than 120 companies in the S&P 500 are set to report their results, including tech names Alphabet, Amazon and Palantir, as well consumer giants, including Walt Disney and Mondelez. 

The January nonfarm payrolls report will also be out Friday, adding color to the employment picture so far this year. Economists polled by Dow Jones expect that 175,000 jobs were added last month. The unemployment rate is predicted to have remained unchanged at 4.1%.

Stocks are coming off of a volatile few weeks. The three major U.S. indexes ended Friday’s trading session in the red, but traders still closed off the first month of the year with gains. The S&P 500 gained 2.7% and the tech-heavy Nasdaq Composite added 1.6% in January, while the Dow Jones Industrial Average outperformed during the period, jumping 4.7%.