Berkshire Hathaway Letters to Shareholders: 1965-2024

by Warren Buffett

Principles of Insurance Underwriting When property/casualty companies are judged by their cost of float, very few stack up as satisfactory businesses. And interestingly — unlike the situation prevailing in many other industries — neither size nor brand name determines an insurer’s profitability. Indeed, many of the biggest and best-known companies regularly deliver mediocre results. What counts in this business is underwriting discipline. The winners are those that unfailingly stick to three key principles: They accept only those risks that they are able to properly evaluate (staying within their circle of competence) and that, after they have evaluated all relevant factors including remote loss scenarios, carry the expectancy of profit. These insurers ignore market-share considerations and are sanguine about losing business to competitors that are offering foolish prices or policy conditions. They limit the business they accept in a manner that guarantees they will suffer no aggregation of losses from a single event or from related events that will threaten their solvency. They ceaselessly search for possible correlation among seemingly-unrelated risks. They avoid business involving moral risk: No matter what the rate, trying to write good contracts with bad people doesn’t work. While most policyholders and clients are honorable and ethical, doing business with the few exceptions is usually expensive, sometimes extraordinarily so. The events of September 11th made it clea...