No, owned by Geely, which owns Volvo as well. It is an attempt from Geely to gain foothold in the western markets without being associated as a chinese brand, but as a swedish one.
I think it's more complicated than that - it was certainly owned entirely by Volvo as recently as 2015 and seems to share basically all engineering resources with Volvo. Seems like a funny attempt somewhere to make it seem like something other than Volvo - not sure why as Volvo has a reputation that's fairly decent already, if a bit dull and parental. I guess that's why Polestar is separate - to be more fashionable. Polestar still 'engineer' Volvos - I think it was at some point like BMW's 'M' thing - like a badge?
Polestar was a firm that did trim and racing cars for Volvo. Volvo did aquire Polestar and a few years later they spun it out to be a ev-company owned 50/50 by Geely and Volvo (and volvo is owned by geely). The cars are designed in Sweden but built in China.
The founders of Polestar now runs the Cyan racing company which is the official racing partner of volvo and geely...
A big difference is that Audi was an established car maker that had made a lot of cars long before VW bought them. Polestar wasn't a car maker before being bought by Geely and has never made car independently of Volvo/Geely.