Credit Risk Fundamentals › Credit Risk Fundamentals

Credit risk is the possibility of financial loss arising from a borrower's failure to repay a loan or meet contractual obligations. While market risk, which we examined in the previous chapter, stems from movements in prices, rates, and volatilities, credit risk arises from the potential deterioration or default of a counterparty's creditworthiness. For banks, insurance companies, and asset managers, credit risk often represents the largest source of potential losses. Understanding and quantifying this risk is essential for pricing loans, setting aside reserves, and making sound investment decisions.

The 2008 financial crisis showed the dangers of poorly understood and mispriced credit risk. Subprime mortgage defaults cascaded through structured credit products, amplified by interconnected counterparty exposures, ultimately threatening the global financial system. What began as localized losses in one segment of the housing market quickly spread into a systemic crisis, showing how deeply credit risk affects modern financial markets. This crisis showed why rigorous credit risk measurement is essential and led to reforms that still shape the industry today.

This chapter introduces the foundational framework for quantifying credit risk through three key components: the Probability of Default (PD), Loss Given Default (LGD), and Exposure at Default (EAD). Together, these parameters allow us to calculate expected losses and inform decisions about loan pricing, bond valuation, capital allocation, and loss provisioning. Building on our earlier discussion of credit default swaps and structured credit products in Part II, we now examine the quantitative mechanics underlying credit risk assessment. By the end of this chapter, you will understand the formulas, the intuition behind each component, and how they work together to provide a complete picture of credit risk.