WASHINGTON — Growth by the U.S. economy fell off sharply in the first three months of 2016, posting its worst quarterly performance in two years amid a global slowdown, the Commerce Department said Thursday.

The broadest measure of the nation’s economic output, known as gross domestic product, increased at an annual rate of 0.5 percent from January through March. That was down from a weak 1.4 percent reading in the fourth quarter and 0.2 percentage points below analysts’ forecasts.

The last time the economy performed worse was in the first quarter of 2014, when severe winter weather in much of the nation caused the GDP to contract at a 0.9 percent annual rate.

This year’s first-quarter slowdown was driven by declines in business investment, exports and federal government spending, the Commerce Department said.

Growth in consumer spending, a key driver of the economy, also declined as Americans became more cautious in the wake of a financial market downturn earlier this year.

The 1.9 percent increase in consumer spending was down from 2.4 percent in the fourth quarter of 2015 and the weakest in a year.