What is Margin of Safety?
Coined by Benjamin Graham in 'The Intelligent Investor,' margin of safety means buying assets well below their estimated intrinsic value. If you calculate a stock's intrinsic value at $80 per share, buying at $50 gives you a 37.5% margin of safety. This cushion protects against analytical errors, unexpected business deterioration, and market downturns. Warren Buffett has called margin of safety the three most important words in investing.
Applying Margin of Safety
Value investors typically require a margin of safety of 25-50% before purchasing a stock. If a discounted cash flow analysis suggests a company is worth $100 per share, a conservative investor might only buy below $60. The required margin varies with uncertainty - a stable utility company might warrant a 20% margin, while a speculative biotech firm might need 50% or more. The concept also applies to bonds, where buying below par value provides a margin.
Key Considerations
Margin of safety is only as reliable as the intrinsic value estimate it is based on. If your valuation model is flawed, even a large margin provides false comfort. During the dot-com bubble, many analysts calculated high intrinsic values for unprofitable companies, and their supposed margins of safety evaporated. Combining margin of safety with diversification across 15-20 positions reduces the impact of any single valuation error on overall portfolio performance.