In the past, China has helped the world out of such weak spots, most notably during the global financial crisis. But this time, its economy is showing pronounced weakness.

Car sales have plunged in China since last summer. Smartphone sales are falling. The real estate market has stagnated, with deeply indebted developers forced to pay steep interest rates to roll over their debts. And trade frictions with the West, coupled with tough policies from Beijing toward foreign investors, have made Chinese and foreign companies alike warier of further investment in China.

“European investment in China is going down,” Cecilia Malmström, the European Union’s commissioner of trade, said during an interview in Washington. “That is more because it is becoming increasingly complicated to do business there, with the forced technology transfer, with the lack of transparency, discrimination as compared to Chinese companies, with the massive subsidies of state-owned companies .”

For the heads of state and corporate leaders gathering this week in Davos, Switzerland, for the World Economic Forum, the Chinese economy could be the most pressing issue, even among the trade fights and political uncertainty plaguing the rest of the world.

China on Monday said its economy grew 6.4 percent during the last three months of 2018 compared with the same time in 2017. For all of 2018, China’s economy grew 6.6 percent, the slowest pace since 1990, though many economists believe the country’s headline figures are unreliable.