>What would it mean if SpaceX buys Tesla though? Does the combined market cap count? That would be wrong.

I took a look at the proxy statement as they have it outlined in this [0] document (Proposal 4). As currently formulated, Musk has 12 operational goals (like ship 1 million robots or hit 50 billion EBITDA) and 12 market cap goals. These need to be paired together for the shares to vest; so, if he reaches the first market cap number, he also needs to fulfill an operating goal for the first set of shares to be earned. These earned shares vest in ~5 years.

This comes with a huge caveat. If Tesla changes control, those operational goals go out the window and his stock award is based solely on market cap (along with the shares immediately vesting). The share price for this is the greater of:

1. The last traded Tesla price prior to the acquisition, or 2. The per share price outlined in the acquisition.

The "easiest" way to take advantage is to IPO SpaceX (which he did), pump up the market cap, acquire Tesla for a sizable premium, and vest as much of the stock award as you can. It means you get to avoid the operational goals entirely and vest a bunch of Tesla (but soon to be SpaceX) stock.

[0]: https://www.sec.gov/Archives/edgar/data/1318605/000110465925...