Columbia Study Flags Potential Understatement of Risk in Private Credit Ratings

Why It Matters

If private ratings are overly optimistic, insurers could be under‑capitalized, amplifying systemic risk and prompting regulators to rethink capital frameworks.

Key Takeaways

• Private-letter ratings assign grades up to three notches higher than public
• Insurers hold about $481 bn in privately rated debt, 12% of holdings
• Private-rated assets face twice the credit loss rate of public peers
• Rating-driven capital rules may incentivize overly favorable private ratings
• Regulators are reviewing private rating practices as insurer exposure grows

Pulse Analysis

The private credit market has exploded to roughly $1.8 trillion, driven by institutional demand for higher yields and better asset‑liability matching. Within this space, private‑letter ratings—issued by agencies such as Egan‑Jones, Kroll and Morningstar DBRS—are increasingly used by insurers and asset managers. The Columbia Business School paper highlights a systematic bias: private ratings often sit two to three notches above comparable public ratings, leading to a credit‑loss incidence that is about twice as high for similarly rated securities. This discrepancy suggests that market participants may be relying on overly optimistic signals when allocating capital.

For insurers, the stakes are high. Around $481 billion of their rated credit holdings—about 12% of portfolios—are now tied to privately rated debt. Because regulatory capital requirements are closely linked to rating grades, inflated ratings can reduce capital charges and encourage deeper exposure to riskier assets. The study’s implication is that insurers could be holding more risk than their capital buffers reflect, potentially compromising solvency in stressed scenarios. Many firms argue that internal risk models and oversight mitigate this gap, but the lack of transparent, comparable ratings erodes market discipline and could distort pricing across the broader credit ecosystem.

Regulators are taking note. State insurance authorities and the NAIC have begun reviewing the growing reliance on private ratings, acknowledging gaps identified in limited‑sample audits. While rating agencies contest the methodology, the academic findings add pressure for greater disclosure and possibly a shift toward model‑based or hybrid rating approaches. Industry groups stress the long‑standing performance of private credit strategies, yet the convergence of higher allocations, opaque ratings, and capital incentives may prompt tighter oversight and a reevaluation of how private credit risk is measured and reported.