Wall Street stocks tumbled early Thursday as consumer spending growth slowed, leaving the S&P 500 on track to conclude the worst opening half to a year since 1970.

Commerce Department data showed spending rose just 0.2 percent in May, less than half the increase in April and part of a steady downward drift as consumers pull back amid surging prices.

The report also showed that the price index rose 6.3 percent compared to May 2021, the same annual pace as in the prior month -- a positive sign in the Federal Reserve's battle against inflation.

About 15 minutes into trading, the S&P 500 was down 1.7 percent at 3,753.55.

The broad-based index has fallen more than 17 percent in 2022 as aggressive Fed interest rate hike to quell inflation has sparked recession worries.

The Dow Jones Industrial Average shed 1.6 percent to 30,519.79, while the tech-rich Nasdaq Composite Index sank 2.2 percent to 10,936.67.

When inflation is taken into account, the data show a decline in real consumer spending, said Lydia Boussour, lead US economist at Oxford Economics.

"We still see some pent-up demand for services such as dining out, travel and entertainment, which should keep a floor under consumer spending over the summer," Boussour said in an analysis. "But the outlook for the fall is more uncertain, with a risk that consumers spending decelerates even more rapidly."