First, the U.S. government’s inappropriate real estate and financial policies paved the way for the crisis.

Home ownership was once part of the American dream.

During the Great Depression of the 1930s, domestic demand in the United States was sluggish. One of Roosevelt's New Deal decisions was to establish Fannie Mae to provide housing financing for the people, help people buy houses, and stimulate domestic demand.

Second, the "abuse" of financial derivatives has lengthened the financial transaction chain and encouraged speculation.

Fannie and Freddie purchase illiquid loans from commercial banks and mortgage companies, convert them into bonds through asset securitization and sell them on the market, attracting investment banks and other financial institutions to purchase them. Investment banks use "superior" financial engineering technology

, then divide, package, combine and sell them.

Third, U.S. monetary policy is adding fuel to the flames.

Low interest rates have prompted American people to invest their savings in assets and banks to issue excessive loans, which directly contributed to the continued expansion of the U.S. real estate bubble.

Moreover, the Fed's monetary policy also "induced" the market to form an expectation: as long as the market is in a downturn, the government will definitely rescue the market, so the entire Wall Street is filled with speculation.

However, when monetary policy was tightened continuously, the real estate bubble began to burst, and the default rate of the low-credit class first increased. The resulting default frenzy began to sweep all financial institutions eager to make money and ambitious.

Extended information: The U.S. subprime mortgage market usually adopts a repayment method that combines fixed interest rates and floating interest rates, that is, home buyers repay the loan at a fixed interest rate in the first few years after purchasing the home, and then repay the loan at a floating interest rate.

As the U.S. housing market cools down, especially as short-term interest rates increase, the repayment interest rates on subprime mortgages have also risen sharply, greatly increasing the loan repayment burden on home buyers.

This situation directly caused a large number of subprime mortgage borrowers to be unable to repay their loans on time, thus triggering the "subprime mortgage crisis."

As the only superpower in the world, the outbreak of the subprime mortgage crisis in the United States instantly affected financial centers around the world and some neighboring countries. Its scope was far from just the subprime mortgage crisis, but spread to the entire financial industry.

Although the U.S. current account deficit has been declining, it still accounts for about 6% of GDP. Because Americans consume far more products than they produce, Americans remain one of the largest sources of demand for the rest of the world. The sharp decline in demand is extremely

It greatly affected the economy of other regions and once caused panic in countries all over the world.