What Is Margin of Safety?

Simple answer

Margin of safety is the gap between a stock's price and its estimated intrinsic value, expressed as a percentage.

Why this matters

A lower purchase price can leave more room for an estimate to be wrong, but it does not limit losses. The estimated value can fall, and a stock that looks inexpensive can still lose most or all of its value.

Good signs

A positive margin of safety means the stock trades below its estimate.

Warning signs

A negative margin means the stock trades above the estimate.

Easy mistake to make

Relying on it alone, or forgetting that the intrinsic value behind it is itself uncertain.

How Wall Street Score helps

Shown as a labeled metric and on the valuation thermometer on the stock page.

Discount and potential upside use different denominators

Hypothetical example: a share price of $80 and an estimated value of $100 give a margin of safety of (100 − 80) / 100 = 20%. A rise from $80 to $100 would instead be a 25% price gain. These percentages answer different questions; neither is a forecast.

Use price and estimated value in the same currency and on the same per-share basis. A zero or negative estimate does not support the usual interpretation of this percentage. Check split adjustments, ADR ratios and the valuation date.

Test the estimate before trusting the gap

At an $80 price, a $100 estimate implies a 20% discount. If weaker cash flows reduce the estimate to $60, the same price is about 33.3% above that estimate. The stock price did not change; the assumptions did.

Compare several scenarios for growth, margins, capital spending and the discount rate. Include debt and other claims before allocating value to common shares. A seemingly precise percentage can hide a wide range of plausible outcomes.

A discount does not limit losses

Buying at a discount to a model does not create a floor under the share price. A purchase at $80 can fall to $40, a 50% loss, or become worthless. No universal 20% or 30% discount prevents permanent loss.

Use the gap to identify questions: is earnings power recurring, are large obligations missing, and can shareholders be diluted? Review the underlying business and financing before treating an apparent discount as attractive. The intrinsic value guide explains the uncertainty behind the estimate.

Further reading and verification

• Investor.gov: Asset Allocation, Diversification and Risk
• Investor.gov: Investing on Your Own — Research Your Investments

References explain the underlying concepts; they do not endorse Wall Street Score's model.

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