Tesla is way overvalued from the fundamental point of view, logic says Tesla can't be half the market cap size of GM if GM produces in 5 minutes what Tesla produces in a day. Okay it is a starter company, I buy that and the big investors jumped in with the hope of a Gigafactory, the revolutionary EV and the impressive Elon Musk's technical genius. But beware, competence is catching up, the Chinese market is shrinking, oil (priced in dollars) has not recovered and Model X won't be seen by customers until it'll be delivered. Tesla is burning cash like rocket fuel in Capital expenditure and had to ask for an asset based credit line of 5000 M besides the CFO quit a privileged position on a growing company, this flashes a big financial warning.
So what's driving the stock? news, events, upgrades/downgrades, rumors, "timed twits". But Elon doesn't have it easy, with 25% float short he has to run with a big Bear on his back and he has to convince the market with facts, met goals and green profits before the market runs out of patience and the bubble inflated with Hope + Greed + Euphoria deflates.