These are securities backed by assets, like mortgages, which are claimable if the creditor defaults.
Other Trading Basics
A Bear Market occurs when the price of a security is falling, and the negative outlook of the security causes the security’s price to continue to fall, causing a self-sustaining problem.
For a downturn like this to be officially considered a bear market, it must be on-going for longer than two months, otherwise it is known as a correction.
Bears are generally traders with a pessimistic view on markets that look to profit from a decline in prices.