An academic-style note on the margin of safety as a valuation principle in long-term value investing. A disciplined value process becomes most fragile precisely when analysis creates the illusion of precision. The margin of safety matters not because valuation is impossible, but because even a well-reasoned estimate

An academic-style overview of the economic moat as a core principle of long-term business analysis. Most businesses with high returns on capital eventually face competition that drives those returns back toward the cost of capital. A small minority, however, sustain excess returns for decades with only limited deterioration.