Typically marketed as low risk, these investments, known as wealth management products, offer tantalizing returns that seem to handily beat the interest rates that banks offer on regular accounts. Lured by the assurances of safety and promises of profit, investors have plowed their savings into the products.

But many of the investments have focused on coal, steel and real estate — areas that are facing overcapacity problems in China. As those areas show signs of trouble, the worry is that many of the investments could fail, creating a major shock to the Chinese economy, the world’s second-largest, after the United States’.

The products, which are often kept off banks’ balance sheets, are part of a vast, shadowy system of lending that has girded the Chinese economy and kept businesses growing. The Chinese government has stepped in to protect investors, avert ripple effects and ensure social stability.

But those bailouts create their own challenges. Investors, assured that the government will come to the rescue, do not worry about the potential risks and continue to pour money into the products. According to the state news media, Chinese investors have put $4.4 trillion into wealth management products, equivalent to about 40 percent of the country’s annual economic output.

“It invites moral hazard,” said Victor Shih, an associate professor at the University of California, San Diego, who specializes in the politics of Chinese banking policies. “When you tell people that they will get bailed out, then they will engage in very, very risky behavior and also opportunistic behavior on the part of the banks.”