What's going on?

Shares of electric car maker Tesla ran out of juice on Thursday: they fell 7% after the company reported fewer-than-expected third-quarter deliveries late on Wednesday.

What does this mean?

Tesla delivered 97,000 vehicles in the last three months � more than it ever has in a single quarter, but still shy of the 100,000 it’d promised investors (tweet this). Fewer deliveries than hoped probably means Tesla�s quarterly revenue and profit will fall short of forecasts too. It�ll pop the hood on those figures later this month�

Why should I care?

The bigger picture: Traffic jammed.

On Wednesday, major US, European and Japanese automakers revealed their American sales fell 12% last month. Only General Motors� sales grew, thanks to a fresh lot of redesigned cars. Consumers typically avoid big-ticket purchases like cars when economic growth starts to slow, even if their overall spending is stable. And if their confidence in the economy is rattled � as it has been lately � that could soon crimp even smaller purchases too. That�ll probably worry investors: they�ve been selling stocks globally this week, perhaps encouraged by fresh data that showed slowing Stateside job creation last month, as well as falling manufacturing activity in the country for two months in a row.

Zooming in: Tesla might have a credibility problem.

Investors tend to take official statements from companies at their word, and � with a little help from its CEO�s �Twitter fingers� � Tesla appears to be getting a reputation for breaking its promises. Some analysts argued on Thursday that the automaker�s reliably unreliable earnings forecasts � essential for investors to assess what the company�s shares are worth � make buying them an unappealing prospect. That might explain why investors have lined up to bet Tesla�s share price will fall, giving it the dubious honor of most shorted stock in America.