He’s already margined a lot of his Tesla shares. The rest is largely illiquid. Tesla shares are expensive to margin, especially for $10bn; we’re seeing an unusually-large consortium of banks assemble to provide that tranche of financing. That implies having to sell large, market-moving stakes in, all likelihood, Tesla and/or SpaceX. Something feasible, but unlikely pleasant for Musk or other shareholders in those names.

Also, Musk is someone who said “funding secured” without funding secured in 2018.

Yes, though that was a Tweet and not an SEC filing

Most people, at this point, believe he has funding. When he first tweeted his bid, however, the stock dropped.

He still has to come up with $21bn. He’s tapped out on margin loans, so that will involve some selling of assets. And market conditions are volatile enough for those funding commitments to fall through.