NEW YORK — Deepening worries about global economic growth, particularly in China, set off a rout in riskier assets such as technology stocks, copper and crude oil Wednesday. U.S. retailers took a drubbing after Macy’s reported weaker sales.

An unexpected drop in profits for Chinese tech giant Tencent surprised investors and added to some recent concerns about the health of China’s economy. Tencent, a gaming and messaging company, is the most valuable technology company in China.

Earlier this week, reports on growth in factory output, consumer spending and retail sales in China were all slower than expected.

Large technology companies, including Alibaba and Baidu of China and U.S. tech giants including Facebook and Microsoft, fell.

Oil prices sank and copper plunged to its lowest price in a year as investors worried about the health of the global economy. The S&P 500 index had its biggest decline since late June while traditionally safe investments like bonds and high-dividend stocks rose.

“This year we’ve seen slower growth. Everyone expected that,” said Kate Warne, an investment strategist for Edward Jones. “Over the last couple of months it looks like growth has been slower than everyone expected.”

The S&P 500 slid 21.59 points, or 0.8 percent, to 2,818.37. Earlier it fell as much as 1.3 percent.

The Dow Jones Industrial Average fell 137.51 points, or 0.5 percent, to 25,162.41. The Nasdaq composite dropped 96.78 points, or 1.2 percent, to 7,774.12. The Russell 2000 index of smaller-company stocks sank 21.91 points, or 1.3 percent, to 1,670.67.

Jefferies & Co. analyst Karen Chan said Tencent’s revenue was also disappointing, mostly because of weak results from its mobile gaming business.

Tencent’s stock fell 3.6 percent in Hong Kong. The U.S.-listed shares of online retailer fell 4.5 percent to $32.36, and web search company Baidu gave up 1.3 percent to $213.47.

U.S. crude sagged 3 percent to $65.01 a barrel in New York, and Brent crude, the standard for international oil prices, lost 2.3 percent to $70.76 a barrel in London.

Copper tumbled 4.5 percent to $2.56 a pound, its lowest price in more than a year.

Copper is considered an important economic indicator because of its uses in construction and power generation, and copper futures have fallen more than 20 percent since they hit an annual high of $3.30 a pound in early June.

Macy’s plunged 15.9 percent to $35.15 after reporting that its sales slowed in the second quarter. Kohl’s shed 5.8 percent to $74.39.

Bond prices rose. The yield on the 10-year Treasury note fell to 2.86 percent from 2.89 percent.

Banks fell because of a sharp drop in interest rates, which make mortgage and other loans less profitable. High-dividend companies like utilities and phone companies did better than the rest of the market. Investors often treat them as an alternative to bonds and buy them when yields fall.

Only subscribers are eligible to post comments. Please subscribe or to participate in the conversation. Here’s why.

Use the form below to reset your password. When you've submitted your account email, we will send an email with a reset code.