Subprime mortgage loans refer to loans provided by lenders to borrowers with poor credit histories or low credit scores. These loans typically have higher interest rates and less favorable terms than prime loans offered to borrowers with good credit. Subprime mortgage loans became popular during the early 2000s to supply credit to low-income borrowers who would not otherwise qualify for a mortgage. Many subprime loans were bundled together as mortgage-backed securities and sold to investors, contributing to the housing bubble and subsequent financial crisis in 2008.

Subprime mortgage loans are used in the financial industry to provide credit to borrowers who may not qualify for traditional mortgages. They allow these individuals to buy homes, but lenders face greater risk due to the higher likelihood of default. Subprime mortgage loans may be packaged into mortgage-backed securities and sold to investors, earning lenders and investors income from the interest paid by borrowers. However, these securities can become risky investments if a large portion of the borrowers default on their loans. In addition, subprime mortgage lending practices became the focus of intense scrutiny following the financial crisis and subsequent reforms were implemented to minimize default risk.