Page 7 of the Acted Notes (section: Approaches to modelling Credit Risk) quotes the Core Reading:
"Structural models are explicit models for a corporate entity issuing both equity and debt. They aim to link default events explicitly to the fortunes of the issuing corporate entity....
An intensity-based model is a particular type of continuous-time reduced-form model. It typically models the jumps between different states (usually credit ratings) using transition intensities. The disadvantage of reduced-form models is that they sometimes lack the clarity of structural models.."
Two questions:
1) Why are structural models called 'explicit' even though F(t) and sigma (the volatility) are unobservable and their valuation requires the Black Scholes assumptions including that F(t) follows Geometric Brownian Motion? Does 'explicit' in this context mean that we evaluate F(t) purely based on current information, rather than requiring estimates of probability of default at a future date?
2) What does the Core Reading mean that reduced-form models 'lack the clarity' of structural models? Does 'clarity' refer to the explicitness of structural models (discussed above) or another characteristic? [I certainly don't have clarity
]
"Structural models are explicit models for a corporate entity issuing both equity and debt. They aim to link default events explicitly to the fortunes of the issuing corporate entity....
An intensity-based model is a particular type of continuous-time reduced-form model. It typically models the jumps between different states (usually credit ratings) using transition intensities. The disadvantage of reduced-form models is that they sometimes lack the clarity of structural models.."
Two questions:
1) Why are structural models called 'explicit' even though F(t) and sigma (the volatility) are unobservable and their valuation requires the Black Scholes assumptions including that F(t) follows Geometric Brownian Motion? Does 'explicit' in this context mean that we evaluate F(t) purely based on current information, rather than requiring estimates of probability of default at a future date?
2) What does the Core Reading mean that reduced-form models 'lack the clarity' of structural models? Does 'clarity' refer to the explicitness of structural models (discussed above) or another characteristic? [I certainly don't have clarity