Contagion refers to the spread of financial problems or crises from one market or sector to others. This can occur when economic conditions or events in one country or region affect financial markets and institutions in other countries or regions, leading to a wider and more severe crisis. For example, the global financial crisis that started in 2008 began with the collapse of the US housing market, but quickly spread to other financial markets and institutions around the world, causing widespread economic disruption. Contagion can be caused by various factors, including interconnectedness of financial systems, cross-border trade and investment, and investor panic or uncertainty.