ALL of them, from the tech giants all the way down to the smallest of "Mom & Pop" stores. They pay their taxes (mostly), then Congress allocates a proportion of those taxes to the DoD's budget, which then spends them on the MIC. Pretty much the same as any country, including China.
The US is stepping onto a very slippery slope here, and if the Chinese start to respond in kind then it's an awfully long way down given it's pretty clear by now that Trump has no clue that playing tit-for-tat isn't a good strategy. They could legitimately start with Boeing and the like, of course, because they directly manufacture military hardware, then move onto the service/support part of the MIC and companies like Microsoft and OpenAI, and if things really get out of control into the supply chain, then that's an awfully big web that is going to reach into some very unexpected places, including some of those "Mom & Pops". The rest of the world will quite naturally want no part of that trade war (which is what this really is), so don't be surprised if this kind of thing just accelerates their on-going pivot away from US suppliers to reduce the impact of any blowback.
Fortunately, as we saw with tariffs, Xi Jinping (and just about everyone else) does seem to realise that is a poor strategy though, so it might not be a fast decent into chaos before sanity prevails, but that also just buys more time for the smarter players to make their pivot towards alternative supply chains.