What is the most valuable startup in the US?

I'm curious, what exactly is the most valuable startup in the United States at this moment? Is it a tech company that's disrupting an established industry, or perhaps a new fintech player shaking up the financial landscape? How did they achieve such a high valuation, and what sets them apart from the competition? With so many startups popping up every day, it's fascinating to see which ones are able to rise to the top and captivate the imagination of investors.