I'm no financial expert, but AFAIU the mechanics of securitization mean that we can assume some multiplier greater than 1x.
You can borrow against your shares at the same time Apple can borrow against its cash holdings and, ceteris paribus, the end result will be more debt than Apple's cash reserves even after considering a reduction in Apple's stock value. And this debt can be used to buy more assets. (Basically, fractional reserve isn't just a banking thing. It's inherent to the mechanics of capitalist finance.)
In addition, the ability to do this enhances capital allocation efficiency, which adds independent value to the entire system.
So there's not a simple function mapping corporate wealth to personal wealth, though you certainly can't simply sum corporate-held assets to personal wealth. I'm happy to be corrected for the implication.
You can borrow against your shares at the same time Apple can borrow against its cash holdings and, ceteris paribus, the end result will be more debt than Apple's cash reserves even after considering a reduction in Apple's stock value. And this debt can be used to buy more assets. (Basically, fractional reserve isn't just a banking thing. It's inherent to the mechanics of capitalist finance.)
In addition, the ability to do this enhances capital allocation efficiency, which adds independent value to the entire system.
So there's not a simple function mapping corporate wealth to personal wealth, though you certainly can't simply sum corporate-held assets to personal wealth. I'm happy to be corrected for the implication.