The distance to default of a firm over a horizon is the number of standard deviations by which the expected log asset value exceeds the default point:
with the real-world asset drift. In the Merton model the real-world probability of default is ; in practice the distance is mapped to default frequencies through a history of defaults, because asset returns are not normal.
أمثلة
Example 14.5 (Two probabilities)
With an asset drift of 8%, the firm’s five-year distance to default is 1.02 and the real-world probability of default 15.4%, against the risk-neutral 32.7% of Example 14.3. The gap is the default risk premium of chapter 13 in structural form: under the risk-neutral measure the assets drift at instead of .