His eye will be on whatever are the most profitable companies, presumably, doubly attractive when they are contractors to the federal government, so that opportunities for corruption are at maximum level. So maybe Meta, Amazon, Alphabet, Apple relatively safe for now?

Got to wonder how the extortion will play out with BAE Systems. A UK-domiciled company can’t legally just give away 10% (or 15% or whatever Danegeld is demanded). But what is the mechanism to extort stakes in wholly-owned US subsidiaries?

I would think it's enough to take a stake in the parent company, which directs what happens at subsidiary level (subject to local laws, presumably).

Extorting a stake in a UK company vital to Britain's national security would be.. interesting.

True, but let's face it, Britain is already heavily dependent for its defence on both the US as a nation and on US arms manufacturers, not to mention the UK nuclear arsenal which the US apparently controls. Practically speaking, the UK is now like, say, Poland was to the USSR.