Is there an HN clone but for stocks/investing?

I would recommend Bogleheads [0] and r/investing [1]. But, these sites don't have the same format like HN. You can see if the design is different.

[0]: https://www.bogleheads.org

[1]: https://www.reddit.com/r/investing

https://stocktwits.com/ ?

Yes, /r/wallstreetbets

wall street oasis comes to mind, but its more of a forum than a news site