As the other poster said, it's a special type of collateralized loan where since everything is known, it can be done automatically.
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.
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.