Event Risk
The risk that an unforeseen, company-specific or market event causes a sudden large change in an investment's value.
What is Event Risk?
Event risk is the possibility that a specific, often sudden and unpredictable event will cause a significant change in the value of an investment or portfolio. In fixed income, event risk traditionally refers to leveraged buyouts, spinoffs, or hostile takeovers that cause a bond issuer's credit quality to deteriorate sharply, widening spreads and marking down bond prices. In equities, event risk encompasses earnings surprises, regulatory actions, executive departures, product recalls, cybersecurity breaches, natural disasters affecting a company's operations, or sudden geopolitical developments. Unlike market risk — which reflects broad economic conditions — event risk is often idiosyncratic and largely undiversifiable at the individual security level, though a well-diversified portfolio reduces its aggregate impact. Event risk is particularly important for investors in concentrated positions, high-yield bonds, and merger arbitrage strategies.
Example
In 2010, the Deepwater Horizon explosion exposed BP to enormous event risk. The stock lost over 50% in two months as the scale of the oil spill liability became clear, dividends were suspended, and regulatory risk mounted. Investors holding a diversified global energy portfolio experienced a much smaller impact than those concentrated in BP.
Source: Investopedia — Event Risk