I would think that everyone (besides Musk) in the two companies would prefer clean lines of origination and transition for IP between the two companies. This me

I would think that everyone (besides Musk) in the two companies would prefer clean lines of origination and transition for IP between the two companies. This means there would be a typical contract between two companies: Company B licenses for a fee the tech from Company A; or Company B acquires for a price the tech from Company A; or, as I saw at my previous startup employer, some kind of partnering arrangement to further develop, together, Company A's tech. I have no idea how it's decided which company owns what in the case of additional development between both companies. The point is: they agree on a contract that hopefully keeps ownership well delineated in the event of an ownership change, or outside lawsuit, or ... whatever legal event may come up.