Most likely, the contract is between Tesla and Musk’s Twitter acquisition vehicle (“X Holdings”), so it isn’t moonlighting, it is their day job. But, even if i

Most likely, the contract is between Tesla and Musk’s Twitter acquisition vehicle (“X Holdings”), so it isn’t moonlighting, it is their day job. But, even if it is moonlighting - all employment contracts allow moonlighting with approval. Many firms are rather sparing in granting that approval - but it is a lot easier to say “yes” to an employee request if you know that’s what the CEO wants you to say.