Well, let's start by saying that we should be comparing Enterprise value not market cap because other than Tesla, car companies tend to have a huge amount of de

Well, let's start by saying that we should be comparing Enterprise value not market cap because other than Tesla, car companies tend to have a huge amount of debt on board (which artificially decreases their market cap). Plenty of the big car companies have multi-hundred billion dollar values. Ford at $200Bn, Toyota at $380Bn, VAG at $270Bn. So it's not unreasonable for a good car company to be worth in the hundreds of billions. Tesla also owns some valuable verticle integration with their battery IP and probably has first mover advantage in procuring the requisite metals. Add to that unwarranted hype around self-driving cars, valuation metrics that are more suited to a tech start up than a car company, and the first mover advantage in the electric car space combined with competitors whose shareholders won't tolerate the investment required to catch up. Most likely something like the Apple Car will be the first point at which the valuation gets properly tested.