Traders work on the floor of the New York Stock Exchange (NYSE) on May 31, 2019 in New York City. Spencer Platt/Getty Images

The Dow fell 355 points, or 1.4%, on Friday as investors agonized over President Trump’s threat to impose escalating tariffs on Mexico.

The S&P 500 lost 1.3%, while the Nasdaq fell 1.5%. The selloff capped the Dow’s sixth-straight losing week, the longest slump since June 2011. The Dow finished below 25,000 for the first time in four months.

The Dow and S&P 500 declined nearly 7% apiece in May, their first losing months since December. The Nasdaq tumbled 8% on the month, its worst May since 2010.

Why this matters: Trump’s vow to impose tariffs on Mexico surprised investors, driving shares of auto companies, beer makers and apparel companies sharply lower. General Motors declined 4%, Corona maker Constellation Brands dropped 6% and Levi Straus lost 7%.

US oil prices plunged 5.5% to a three-month low of $53.50 a barrel, reflecting fear about the economic impact of the tariffs on China and Mexico. Crude tumbled 16% in May, snapping a four-month winning streak.

Investors fled to the safety of US government debt, driving the 10-year Treasury yield to 2.13%, the lowest level in nearly two years.

The Mexican peso declined 2.4% against the US dollar, while ETF that track Mexican stocks plunged 4%.