What are mortgage-backed securities?
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What Are Mortgage-Backed Securities (MBS)?
Mortgage-backed securities (MBS) represent a special class of financial securities.
An MBS is a type of debt instrument that is backed by one or more mortgage loans. Banks that originate large numbers of similar mortgages can bundle them together and sell this pool of loans to a government agency or an investment bank. These institutions then package the mortgages into a tradable financial product that investors can purchase.
In many cases, government-related institutions are involved in this process. Some organizations are fully government-owned, such as the Government National Mortgage Association (Ginnie Mae). Others, including the Federal National Mortgage Association (Fannie Mae) and the Federal Home Loan Mortgage Corporation (Freddie Mac), operate as government-sponsored enterprises (GSEs).
Investors who hold mortgage-backed securities usually receive regular monthly payments. These payments come from homeowners who are repaying their mortgages, as their monthly installments are passed through to investors holding the securities.
Mortgage-Backed Securities and the Global Financial Crisis
Mortgage-backed securities played a significant role in the global financial crisis of 2007–2008. One of the main contributing factors was the rapid expansion of subprime mortgages, which were loans issued to borrowers with weak credit profiles.
These loans were particularly risky because many borrowers had poor credit histories, limited assets, or even unstable income sources. Despite this, banks continued approving such mortgages. Their reasoning was simple: once the loans were issued, they could bundle them into mortgage-backed securities and sell the risk to investors.
Credit rating agencies also contributed to the problem by assigning high credit ratings to many of these packaged securities. This gave investors the impression that the products were safe and reliable investments.
When large numbers of borrowers began defaulting on their mortgages, the value of these securities collapsed. The resulting wave of defaults triggered a chain reaction across the financial system, ultimately causing one of the most severe economic downturns in modern history.
Even though mortgage-backed securities were heavily criticized for their role in the crisis, the market for them still exists today. However, because of their complicated structure, controversial history, and relatively high minimum investment requirements — often around $10,000 or more — they are generally avoided by many individual investors.