Usual disclaimer: TSLA shareholder
Personally, I don’t think their valuation is irrational. They’re not a car company, they’re an energy storage company, the market for which is enormous.
A bit down the page on the right, you'll see "Shares Short", "Short Ratio", "Short % of Float", and "Shares Short (prior month)".
What that is telling you is that almost $10B of Tesla stock has been borrowed and sold (with the profit coming from buying in the future at lower prices, ie, betting against TSLA). That is increased about 7% from the prior month, and would take almost 5 entire days of average trading volume to close out all the short positions.
This is a high level of betting against a stock by any standard.
I wouldn't say so. There are other heavily shorted stocks that have a much higher short ratio because of their small float (e.g. MTCH).
>but is there a good way to determine who?
Short sellers don't have to disclose their positions, unlike investors who're long the stock. You can try to get a better sense of who's thinking what through headlines and analyst notes/reports.
Side note: Elon tweeted out that we'd see the 'burn of the century' (a short squeeze) and that it would be bigger than the VW/Porsche squeeze in 08.
If there's a way to report who is short a stock, I don't know it. There are also other trades to profit from decreases in an underlying security (buying puts, selling calls) and I don't know about reporting obligations there, either.
1. https://www.cnbc.com/2016/04/01/tesla-short-interest-hits-re...