I'm sure you already know this, but the deal has already been financed. He is not buying the whole Twitter by himself, just the majority. If co-investors bail out, investment banks who signed the deal take those stocks.

If you compare the purchase price to what Twitter likely would cost without the deal–using the price change of other social media platforms and internet ad platforms as a benchmark–it seems likely that Musk is paying ~$20 billion over the current market value.

If Musk wants to offload even more stocks, he takes huge haircut. At least 50% or more. It's likely better to wait for better times and restructure Twitter.

No matter how you look at it, this is horrible deal for Musk unless he can make Twitter shine again.