I mean it’s a complete and total wild ass guess but the obvious reason to change one’s name is if you’ve identified another entity that is using that name in a way which could prevent you from global exclusive use of the brand.
It’s the kind of thing that could easily have come up in due diligence for the large recent investment.
Doing a quick search of TESS2 for trademarks look they already have the trademark registered for ZEIT (registered in 2017). So it was probably for other reasons. Which is a shame, because Zeit is very concise, easy to remember, and has a strong brand today - at least with their initial audience.
Sounds like they're trying to go for a more corporate customer with their new name.
> Vercel strongly connects to the words versatile, accelerate, and excel.