In financial economics, systemic risk refers to the possibility that the failure of one or more financial institutions or markets could trigger a chain reaction of defaults, credit freezes, or market disruptions, ultimately threatening the stability of the entire financial system.

Systemic risk is often associated with the interconnectedness and complexity of modern financial systems, where problems at one institution or in one market can quickly spread to others.

It can arise from various sources, including:

• Interconnectedness: When financial institutions are highly interconnected through lending, borrowing, trading, or other financial relationships, problems at one institution can quickly spread to others.
• Concentration: When a small number of large institutions dominate a particular market or sector, their failure can have a disproportionate impact on the overall financial system.
• Leverage: When financial institutions or markets are highly leveraged, meaning they rely heavily on debt financing, they may be vulnerable to sudden changes in asset prices or credit conditions.
• Complexity: The increasing complexity of financial instruments and markets can make it difficult for regulators, investors, or market participants to fully understand or manage risks.

Systemic risk can have severe economic consequences, including widespread job losses, business failures, reduced economic growth, and increased public debt. It can also lead to a loss of confidence in the financial system and undermine the stability of the broader economy.

Preventing or mitigating systemic risk requires effective regulation, risk management, and coordination among financial institutions, markets, and policymakers. This may include measures such as capital requirements, stress testing, and macro-prudential policies to monitor and manage risks at the system-wide level.