Subprime borrower: Has a few overdue credit card bills; goes to a storefront lender owned by major bank; takes out a $100,000 home-equity loan at 11 percent interest

Lending bank: Assuming housing prices will only go up, and that investors will want to buy mortgage loan packages, makes as many subprime loans as it can

Investment bank: Packages subprime mortgages into bundles called collateralized debt obligations, or cdos, then sells those cdos to eager investors. Goes to insurer to get protection for those investors, thus passing the default risk to the insurer through a "credit default swap."

Insurer: Thinking that default risk is low, agrees to cover more money than it can pay out, in exchange for a premium

Rating agency: On basis of original quality of loans and insurance policy they are "wrapped" in, issues a rating signaling certain slices of the cdo are low risk (aaa), medium risk (bbb), or high risk (ccc)

Investor: Borrows more money from investment bank to load up on cdo slices; makes money from interest payments made to the "pool" of loans. No one loses—as long as no one tries to cash in on the insurance.

Casey Miner is a Senior Editorial Fellow at Mother Jones