This breaks down to:
a) $21 billion of Elon's ("Reporting Person"; see item #1) own money
b) $12.5 billion in margin loans arranged by Morgan Stanley
c) $13 billion in debt from Morgan Stanley
a) $21 billion of Elon's ("Reporting Person"; see item #1) own money
b) $12.5 billion in margin loans arranged by Morgan Stanley
c) $13 billion in debt from Morgan Stanley
You can get approved for a margin account at TD Ameritrade right now, and then later decide to margin some shares for whatever reason. The bank doesn't need to check your collateral because it knows how much it is worth at any given moment when the market is open.
Mortgage loans are not nearly as formalized, and the bank will send out an appraiser to verify that the property is worth an amount that they're willing to loan against.
And once you get past that, it becomes very hand-wavy; banks making loans to governments, non-profits, private companies, etc will all have their internal departments that make decisions about how much the risk is and what premium they'd need to charge.
The major feature of a margin loan versus other types of loans collateralized by assets is that the value of the underlying security (collateral) is tracked and depending on the terms of the margin loan, the lender has the right to issue a "margin call" demanding additional collateral or cash if the underlying securities have declined in value. These rules, called "house requirements," vary from lender to lender.
If you're MS, why would you want to treat stock as "normal" collateral instead of using a margin loan? Is that Elon only feels comfortable using so much of his stock for a margin loan, and wants to use the rest as "normal" collateral (but is then getting less favorable terms for it)?
It's also possible that Elon is getting a lower rate for the non-margin loan, but at a much worse multiple (putting up far more shares as collateral).
But that's all making stuff up.