Tesla founder Elon Musk’s personal fortune has trebled this year to more than US$90 billion (approx £67 billion).

The Telegraph reports that Tesla, share price has risen more than three hundred per cent this year, meaning it has overtaken Toyota as the world’s most valuable car brand.

But the industry is asking why. ““The share price is ridiculous when you compare it to other car manufacturers and especially if you look at the volume of vehicles that Tesla delivers versus someone like Ford or Toyota,” Policy Manager at Access Partnership Tiernan Kenny told the newspaper.

Tesla sold 367,500 units last year, a record for the company, by comparison Toyota shipped 10.74 million. Despite this, on July 1, Tesla shares hit $1,134 pushing its valuation to $209.47 billion, and it’s now $4 billion higher than Toyota.