[londons_explore]

Is it any different than just having a tax on purchasing foreign companies?

It's the same as a tax on purchasing foreign goods, which is already in place for goods from China in the form of tariffs.

[InitialLastName]

Tariffs aren't a tax on purchasing foreign goods. I can buy as many tons of steel as I'd like in China while paying no money to the US Government (as long as I can export the money, which is a different issue). Tariffs are taxes on importing foreign goods. That would only even conceivably be comparable if Microsoft were planning to relocate TikTok to the US; as it sounds like they're planning to relocate it to London, that wouldn't apply.

[rsynnott]

I mean, if such a tax existed, sure (though such a tax would probably not be a great idea...). However, there is no relevant tax.

[pjc50]

Forgive me if I'm not familiar with the process, but aren't taxes set by Congress?