C'mon, you're bringing up one stock out of the many thousands that are traded on the stock exchange. Your collateral against homes purchased in Arizona, Florida, and Nevada were equally in trouble in 2007, and many lenders had to eat the losses. Does that mean we should get rid of borrowing to finance a home purchase? Of course not.Stocks are no different. In fact, given their liquidity, they can be better collateral than homes, cars and education.