24.7.2. Sam is tasked with evaluating the firm's exposure to credit risk arising from its extensive portfolio, which includes corporate bonds, loans, and structured credit products. The firm seeks to refine its risk management strategy by selecting a credit risk model that offers dynamic adaptability to market conditions, accurate default probability estimation, and considers the firm's specific portfolio characteristics.

Sam reviews four key credit risk models: the Merton model, CreditRisk+, CreditMetrics, and the Moody’s-KMV model. Each model presents unique features and assumptions:

• The Merton model utilizes the firm's equity volatility to estimate the probability of default, treating the firm's capital structure as a call option on its assets.
• CreditRisk+ is an actuarial model focusing on the probability of default based on debt rating and sensitivity to risk factors, employing a Poisson distribution to model credit events such as bankruptcy.
• CreditMetrics employs a mark-to-market approach, emphasizing credit rating transitions and the valuation impact of credit events on the portfolio, using a comprehensive set of market data.
• The Moody’s-KMV model, an evolution of the Merton model, utilizes market data to estimate default probabilities with its Expected Default Frequency (EDF) model, providing continuous updates based on market conditions.

Sam evaluates which model would best suit the firm's needs, given the firm's requirement for a model that adapts dynamically to changing market conditions and accurately estimates default probabilities while considering the specific characteristics of its portfolio.

Considering the need for dynamic adaptability, accurate default probability estimation, and suitability for a diversified financial portfolio, which credit risk model should Sam recommend for the firm’s risk management strategy?