The majority is due to the fact that Tesla's valuation skyrocketed in 2020-2021. The second-largest car maker by market cap is Toyota at 217B. (They're about double VW group, the next-largest.)
Tesla's market cap is now 740B. For a while there it was over 1T. Here's a fun visualization:
Tesla's market cap is now 740B. For a while there it was over 1T. Here's a fun visualization:
https://www.youtube.com/watch?v=zRQlsDHbl0M