Is 10x borrowing even an option if we are talking retirement savings?
I don't know much about finance. I guess that at that point (you borrowed 10 times your net worth). This is no longer your investment, it's your lender's investment. They will adjust interest rate to match the riskiness of whatever you are doing, leaving you with net zero.
> Is 10x borrowing even an option if we are talking retirement savings?
Of course it is, though not exactly by "borrowing money" in a "mortgage" sense. Margin trading is a way to take leverage, derivatives is another. The former is simpler but costly, the latter is cheaper and allows you much more than 10x leverage, though it requires some high school mathematical thinking.
I don't know much about finance. I guess that at that point (you borrowed 10 times your net worth). This is no longer your investment, it's your lender's investment. They will adjust interest rate to match the riskiness of whatever you are doing, leaving you with net zero.
Borrowing money is not free.