The list of the top 10 highest-valued private companies this year is constantly changing as valuations fluctuate. However, based on recent updates, here is a list of some of the highest-valued private companies as of 2021:

1. SpaceX
2. Stripe
3. Palantir Technologies
4. ByteDance (the parent company of TikTok)
5. Instacart
6. Klarna
7. Didi Chuxing
8. Epic Games
9. Airbnb
10. Robinhood

Note that the rankings and valuations of these companies may vary depending on the sources and recent market conditions.