ROIC (Return on Invested Capital) is a widely used metric for evaluating capital efficiency, but it has significant limitations when applied to insurance businesses. Here's why:

Challenges with ROIC for Insurance

1. Balance sheet-driven model. Insurers collect premiums upfront and pay claims later. The "invested capital" base is dominated by float (policyholder reserves) and regulatory capital requirements, not traditional operating assets like factories or equipment. This makes the denominator fundamentally different from industrial companies.

2. Float distorts the picture. Insurance float — premiums held before claims are paid — is technically a liability, not invested capital. Yet it's the engine of profitability. A company with massive float may show artificially high ROIC because invested capital excludes this key resource.

3. Investment income is core operations. Insurers earn substantial returns from their investment portfolios (bonds, equities). ROIC blends underwriting results with investment returns, making it hard to separate operational skill from market conditions or asset allocation decisions.

Better Metrics for Insurance

• Combined ratio (loss ratio + expense ratio): The gold standard. Below 100% means underwriting profit; above means underwriting loss. Clean, comparable, and focused on core operations.
• Return on Equity (ROE): More commonly used and comparable across the sector since equity includes the capital base supporting float.
• Underwriting ROE: Decomposes returns into underwriting vs. investment components.
• Growth in book value per share: Reflects the compounding engine insurers aim for.

In short, ROIC isn't useless for insurers, but the combined ratio and ROE are more informative and more widely used by industry analysts for peer comparison and performance assessment.