What Is a Hazard Rate?
A hazard rate measures how quickly the risk of an event is building for something that has not yet experienced it. In finance it is most often applied to the chance that a borrower defaults on a bond or loan, or that a company goes bankrupt. Unlike a simple probability over a full period, the hazard rate is expressed per unit of time and is conditional on survival. It applies only to the subject that is still "alive," meaning it has not yet defaulted, at the moment it is measured.
How It Works
The concept comes from survival analysis, a branch of statistics first developed for medicine and engineering. Life insurers use the same idea to describe mortality risk at each age. If the hazard rate at time t is written h(t), then the probability that the event occurs in a very short interval after t is roughly h(t) multiplied by the length of that interval, provided the event has not already happened.
Over longer periods, the hazard rates are combined to produce a survival function, which gives the probability that the subject lasts beyond a given time. The relationship can be written as:
Survival probability to time T = exp(−∫ from 0 to T of h(t) dt)
A higher hazard rate produces a faster drop in the survival curve, which means the event is more likely to happen sooner.
Why It Matters to Investors
In credit risk analysis, hazard rates help translate observable market data into estimated default risk. For example, analysts may use a credit spread, the extra yield a corporate bond pays over a safer benchmark, to infer an implied hazard rate and then an implied probability of default over a set horizon. Tracking how the implied rate changes over time can show whether near-term risk appears to be rising or easing.
Hazard rates are estimates, not certainties. They depend on the model's assumptions, the quality of the input data, and how well the model fits real outcomes. Different methods can produce different results from the same market prices, so the figures are best read as one part of a broader risk picture rather than as precise forecasts.
Updated November 5, 2026. For general education only; not financial, tax or legal advice.