You have $100M of stock in Berkshire Hathaway. You use use that as collateral to borrow $11M. You use $1M of the loan to pay expenses (including the interest

You have $100M of stock in Berkshire Hathaway. You use use that as collateral to borrow $11M. You use $1M of the loan to pay expenses (including the interest on the loan). You invest the other $10M in Amazon. A year later you have $11M in Amazon stock and $110M in Berkshire Hathaway. You borrow against the Amazon stock and use that to pay off the first loan. Lather, rinse, repeat. The bankers are always happy. Why would they ever foreclose on you?