Citron Research, the stock-commentary site with a long history of opining on Tesla Inc., thinks even Elon Musk would short the electric-car maker’s shares at this level.

The researcher founded by Andrew Left tweeted Tuesday that Tesla’s own chief executive officer would bet against the stock if he were a fund manager, calling the shares “the new Wall St casino.” The stock soared as much as 21 per cent intraday and has already doubled this year.

Citron publicly announced it was shorting Tesla at least as early as in 2013. Left, 49, sued Musk, 48, in September 2018, after the billionaire CEO claimed he was considering taking the carmaker private at US$420 a share.

But Citron announced a change of heart the following month, with Left writing that Tesla was “smoking” the rest of the auto industry and stealing customers from the likes of BMW AG and Toyota Motor Corp.