I don't know and depends how they proceed about it - e.g. they can just add Russian companies related to Putin's inner circle to the "entities list" like they did with Huawei. That would forbid any business on the US market from selling to the barred Russian companies ( that's why Huawei had to do their own OS, Android was no longer possible due to Google being forbidden from working with them). That would be a fairly benign type of sanction; or they could go Iran style, by blocking them out of the world financial/banking systems, and forbidding anyone from dealing with Russian companies ( a few years ago they fined a French bank, BNP Paribas, for dealing with Iran, so it is anyone, not just American companies). That would be the nuclear option and would harm Russia a lot, but also the EU ( technically they wouldn't be able to pay for the gas bought from Gazprom), and certainly push Russia into an alternative financial and banking system with China, which isn't great.
À propos, Renault were worried about the supply chain for their Russian factories, with IIRC around 20-30% of components coming from places where sanctions could impact them.
Sanctions do definitely have the potential to just push their target towards independence. That's why closing down things like social media would be a risk: closing off the last paths to ordinary Russian citizens is not a good idea for information "warfare".
À propos, Renault were worried about the supply chain for their Russian factories, with IIRC around 20-30% of components coming from places where sanctions could impact them.
PS: https://news.ycombinator.com/item?id=30453503 this just popped on my feed so i posted it on HN to discuss