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.

U.S. stock-index futures opened sharply lower and oil prices jumped Sunday night and investors braced for volatility across financial markets after President Donald Trump over the weekend announced heavy tariffs on imports from Canada,

The selloff offered an early glimpse of how Wall Street will respond to trade wars.