Tesla Motors fell as much as 10% on Monday, adding to a slide that's brought the shares to their lowest level in two years.
They are now trading below $150 apiece, down about $90 from where they ended 2015.
Investors are worried that production delays will put undue strain on the company's balance sheet.
Morgan Stanley analyst Adam Jonas laid out his fears in a five-point note on Monday morning. The problem, specifically, is the delayed launch of the Model X SUV.
From the note:
The potential impact on cash flow could be more significant than the market has anticipated and the market timing potentially compounds the issue. In our recent note and price target reduction to $333 from $450, we factored in a greater level of cash consumption into our earnings model in part to factor in higher levels of launch-related engineering expenses to ensure a high quality ramp of the Model X sufficient to deliver on our estimate of 15k units in 2016.
It seems Jonas thinks that the Model X situation could easily get worse, too. Last month, a lawsuit revealed that Tesla had more trouble manufacturing the car's complicated winged doors than anyone previously thought.
The Model X prototype debuted in early 2012, but the production version of the $80,000 electric SUV didn't launch until the end of last September.
If that situation deteriorates even further, "we would be prepared for alternative design plans and greater levels of spending," Jonas wrote.
He's waiting for the fourth-quarter conference call this week to hear more.
In the meantime, this brings up an ultimate, existential question about Tesla's business model: Can the company scale quickly and efficiently into a sizeable car company without manufacturing partners?
If it can't, it doesn't matter if Elon Musk is trying to change the world with an incredibly cool car if he can only make and sell tens of thousands of them at a time.
That's something Wall Street is starting to notice.
