ValuationIntermediate

Margin of safety

The margin of safety is the distance between price and a prudent valuation. It protects against estimation errors, not against any loss.

3 min read Practical guide

By the end

You will adjust the discount required to quality, uncertainty and possibility of permanent damage.

Why does it exist?

Targets depend on assumptions. The more cyclical, indebted or unpredictable the business, the greater the potential for error and the greater the reasonable discount. A stable company may require less margin, never zero.

It is not a fall from highs

The all-time high does not determine value. A stock down 70% may remain expensive if earnings collapsed; another near high may offer value if the box grew faster.

Example

Prudent value 80 and price 60: 25% margin on value. If the adverse scenario is worth 35, there is still a risk of loss 42% from the price.

Range and probability

Build scenarios with reasoned weights or, at a minimum, observe adverse and central. The margin must coexist with position size: a large discount does not justify concentration if there is a risk of bankruptcy.

Revision

The margin changes with price and fundamentals. If the estimated value drops, maintaining the old target is anchoring. Records assumptions and updates when profit, balance sheet or cost of capital changes.

Prudent value.

Adverse scenario.

Balance quality.

Sensitivity.

Compatible size.

From data to a decision

How much error can valuation absorb?

This guide cannot predict the next move on its own. It can build a conditional reading: what supports upside, what increases downside risk, and which evidence must appear before acting.

Favourable reading

Price remains reasonable under somewhat worse assumptions.

Adverse reading

Upside exists only in the optimistic case and any delay destroys value.

Required confirmation

Compare price with the conservative case, not only the base case.

Reasoned example

A 120 base and 95 bear target versus price 90 offers more protection than 120 base and 55 bear.

Applied workshop

Turn the explanation into a process

Follow these steps in order and keep the result, so you can repeat the analysis and identify what changed your decision.

1Define a value range with explicit scenarios and probabilities.
2Demand a larger discount when balance sheet, cycle, governance or data quality deteriorate.
3Separate volatility from impairment: a price fall creates no margin if value also falls.
4Set price, size and review evidence before the market reaches your level.

Review questions

Which estimation error does the discount absorb?
Could the loss be permanent?
Does the margin remain after costs and taxes?

Worked case

Central discount and adverse damage

Center value 100 and price 70 offer 30% margin on value. But adverse scenario 35 implies potential loss of 50% from price. Central discounting does not eliminate negative asymmetry.

Adjust size and margin to debt, cyclicality and data quality. If the value drops, do not keep the target by anchoring.

Decision rule

Simultaneously observe distance to the centre-back and damage to the opponent.

Put it into practice

Calculate margin against the central value and loss against the adverse value. Decide if the asymmetry is worth the risk.