First of all, the characteristics of financial derivatives determine the development of subprime loans. In the United States, financial derivatives have developed rapidly and widely. Bonds can be packaged with various collateral and issued as financial bonds. For example, the collateral in the subprime mortgage is the subprime mortgage itself, which is so risky that no matter what form of financial assets are gradually forming a bond trend, people who buy subprime bonds simply don't know what the risk is. Because the credibility of financial bonds is still relatively good, the market generally recognizes that bonds can circulate normally and financial institutions can continue to raise funds. However, due to the strong liquidity of bonds themselves and frequent and extensive transactions, subprime bonds have returned to financial institutions. At this time, financial institutions have been unable to continue to pay their debts, and inferior assets packaged as high-quality assets have flowed into their own hands, slowly forming a debt crisis.