What's happening

Shares of Chinese electric-vehicle maker NIO (NYSE:NIO) were down on Wednesday afternoon after the company said that its top finance executive had resigned.

As of 2 p.m. EST, NIO's American depositary shares were down about 12% from Tuesday's closing price.

So what

In a regulatory filing early on Wednesday, NIO said that its vice president of finance, four-year company veteran Dongning Wang, had resigned. His successor will be Yu Qu, who has held "several senior management roles" at NIO since Oct. 16, the company said.

Wang's resignation follows that of his former boss, Louis Hsieh, who resigned as NIO's chief financial officer on Oct. 28 following a report that a $707 million financing deal had collapsed.

A red NIO ES6, an upscale five-passenger crossover SUV.

NIO spent big to launch its ES6 SUV in the second quarter and is now believed to be running low on cash. Image source: NIO, Inc.

Here's why it's important: NIO is thought to be running very low on cash. The company disclosed in September that it had burned more than $600 million in the second quarter, leaving it with just $503.4 million as of June 30.

That was almost certainly not enough to last beyond the end of 2019, and there have been signs that NIO has been scrambling to find additional financing.

Now what

NIO's stock surged more than 30% on Tuesday following news that it had signed a deal with Intel subsidiary Mobileye to make self-driving taxis. But the resignation of Wang, along with the company's apparent unwillingness to explain exactly what's going on, has brought investors' concerns about the company's cash situation back to the fore. Trade carefully.