Stock futures tumbled early Monday as investors weighed new U.S. tariffs on goods from key trade partners and their potential impact on the economy and 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,

(Reuters) -Futures for Wall Street's main indexes tumbled on Monday as fears of a full-blown trade war and its impact on the global economy jolted markets around the world after President Donald Trump levied steep tariffs on Mexico,