What happened

Shares of Chinese electric-vehicle maker NIO (NIO 0.17%) were trading lower on Thursday amid a broad market sell-off driven by growing concerns about the potential effects of rising interest rates in the United States.

As of 2:00 p.m. EST, NIO's American depositary receipts were down by about 8.5% from Wednesday's closing price, while the S&P 500 index was trading about 2.5% lower.

So what

NIO has already had a tough week, and it's only Thursday. The company's fourth-quarter loss of $0.16 per share, reported on Monday afternoon, was worse than Wall Street had expected given NIO's strong sales numbers. 

While the automaker's business generally seems to be on track, that earnings miss raised some questions among investors who were already a bit nervous about its sky-high valuation. NIO's rate of sales growth may also be moderating, another reason for concern. 

Two NIOs parked outside its Silicon Valley office.

NIO is still executing well, but its sales may be slowing, and its wider-than-expected loss has investors concerned. Image source: NIO.

Those concerns have intensified as the week has gone on, with NIO and other high-flying growth stocks continuing to sell off.

Now what

There are two new macroeconomic issues underlying investors' recent bearishness. First, the $1.9 trillion COVID-19 relief package moving through the U.S. Congress has some onlookers worried about inflation, if only because that's a lot of money to pour into the economy more or less all at once.

Second, and relatedly, the yield on the benchmark 10-year U.S. Treasury bond has been rising, and hit its highest level in over a year -- 1.50% -- on Thursday afternoon. While that's still quite low by historical standards, rising interest rates generally lead investors to reduce their exposure to risk. 

Taken all together, that's why NIO stock is down Thursday.