Survival First: The Maths of Losses and Avoiding Permanent Loss

Large losses are far harder to recover from than they look: a 10% loss needs an 11% gain to get back to even, but a 50% loss needs 100% and a 90% loss needs 900%. Because of this asymmetry, avoiding big, permanent losses matters more to your long-term wealth than finding the next big winner. Survival is not a cautious goal. It is the precondition for compounding.

Warren Buffett’s often-quoted rules are “Rule No. 1: Never lose money. Rule No. 2: Never forget Rule No. 1.” People dismiss this as impossible, since every investor has losing positions. They miss the point. The rule is about the arithmetic of catastrophic loss, and about building a process that keeps you out of it.

Where this fits: this is the “why” behind Criterion 4, sound balance sheet, of the Five Criteria, and behind our rule to size positions so you survive being wrong. The Criterion 4 tests themselves are in our hub, how much debt is too much.

The Maths of Losses: Why -50% Needs +100%

When you lose money, you have less capital to earn it back with. So the gain needed to recover is always larger than the loss, and the gap widens fast as losses grow.

Gain needed to recover = loss / (1 - loss).

Loss	Gain needed to break even	Years to recover at 7% a year
10%	11.1%	About 1.6
20%	25%	About 3.3
25%	33.3%	About 4.3
33%	50%	About 6.0
50%	100%	About 10.2
75%	300%	About 20.5
90%	900%	About 34

Read the last column slowly. At a solid 7% a year, a 50% loss costs you about a decade. A 75% loss costs you about twenty years. A 90% loss is, for most people, the end of the road.

Small losses are an ordinary part of investing and cost little. Large losses do damage out of all proportion to their size. That is the whole case for putting survival first.

Compounding Needs Unbroken Time

Consider two hypothetical investors, each starting with $100,000 and investing for 30 years.

Investor A earns an excellent 15% a year for 20 years, reaching about $1.64 million. In year 21, a large speculative bet goes wrong and the portfolio falls 80%, to about $327,000. Investor A goes back to earning 15% a year for the final nine years and finishes with about $1.15 million.

Investor B earns a steadier 10% a year for all 30 years and never suffers a catastrophic loss. Investor B finishes with about $1.74 million.

Investor A	Investor B
Annual return in normal years	15%
Catastrophic loss	One 80% loss in year 21
Value after 30 years	About $1.15 million

Investor A was the better stock picker in 29 years out of 30. Investor B ended with about 50% more money. One avoidable disaster outweighed decades of skill.

Morgan Housel makes a similar argument in The Psychology of Money: the ability to stay in the game long enough for compounding to work matters more than any single brilliant decision.

You Only Get One Path

Averages can mislead. A strategy that works brilliantly in 90% of scenarios but wipes you out in 10% may have a great average result across many imaginary investors. But you are not many investors. You live one sequence of years, and you can only be ruined once.

Nassim Taleb has written about this in Skin in the Game: what matters is the result along your own path through time, not the average across a crowd. For an individual investor, any strategy with a real chance of irreversible ruin is unacceptable, however good its average looks.

How Permanent Losses Actually Happen

Howard Marks has long argued that the risk that matters is the risk of permanent loss, not price volatility. Our guide to investment risk covers this in full. Prices fall and recover all the time. Permanent losses usually come from one of five places:

1. Leverage in the company. A business with too much debt can be forced into a dilutive share issue or bankruptcy in a bad year. Shareholders are paid last.
2. Leverage in your account. Margin debt can force you to sell at the bottom, turning a temporary fall into a permanent one.
3. Overpaying. Buying a good business at a silly price can mean a decade of poor returns, even if the business does well. See the largest risk to your wallet: overpaying.
4. Owning a broken business. When a moat disappears or a product becomes obsolete, patience cannot fix it.
5. Oversized positions. A single stock that is too large a share of your portfolio can do irreparable damage on its own.

The Five Criteria are built to block each of these. Criterion 4 handles the first. The others are covered by price (Criterion 5), business quality and moat (Criteria 1 and 2), and position sizing.

How Company Debt Turns a Setback Into a Permanent Loss

Here is the link to Criterion 4 in numbers. Imagine two hypothetical companies, each with a business worth 1,000 (in millions of dollars). Company X has no net debt. Company Y has net debt of 600.

A recession knocks 30% off the value of both businesses, to 700.

Company X (no net debt)	Company Y (net debt 600)
Business value before	1,000
Equity value before	1,000
Business value after a 30% fall	700
Equity value after	700 (-30%)
Gain needed to recover	43%

The businesses fell by the same amount. Company Y’s shareholders lost 75%, because the lenders’ claim did not shrink. Worse, at that point Company Y’s lenders may demand repayment, forcing a share issue at the bottom that makes the loss permanent.

This is why Criterion 4 requires net debt of no more than 2.0 times EBITDA, interest coverage of at least 5 times and a dividend covered by free cash flow. Those limits keep the companies you own on the Company X side of this table. You check them on the balance sheet and income statement.

Position Sizing: Surviving Your Own Mistakes

Even careful research is sometimes wrong. The question is what happens to your portfolio when it is.

Position size	Portfolio loss if it goes to zero	Gain needed on the rest to recover
5%	5%	5.3%
10%	10%	11.1%
20%	20%	25%
40%	40%	66.7%

A 10% position that goes to zero hurts but is recoverable in a normal year or two. A 40% position that goes to zero can set you back most of a decade.

That is why the Five Criteria say to concentrate only in businesses that pass all five, and to size each position so you survive being wrong. Our guides to position sizing and how many stocks to own cover the details.

A Practical Survival Framework

• Own businesses with sound balance sheets. Apply the Criterion 4 tests to every holding.
• Do not use margin debt for long-term investing. It creates forced-sale risk at exactly the wrong time.
• Invest only money you will not need for at least five years. Otherwise you may be forced to sell in a downturn.
• Keep a cash reserve. It stops you selling at the bottom and lets you buy from those who must.
• Size positions so a single failure is survivable.
• Insist on a margin of safety in price. Paying less means less can go wrong.

How We Use This in the Five Criteria

Survival thinking runs through the whole framework, but it is most concrete in two places:

• Criterion 4, sound balance sheet: net debt/EBITDA of 2.0x or less, interest coverage of 5x or more, and free cash flow covering the dividend. We also cut EBITDA by 30% to see whether the company would stay safe in a recession.
• Position sizing: concentrate only in businesses that pass all five criteria, and size every position so that being wrong is painful but survivable.

Risk, for us, means permanent loss of capital, not volatility. A stock that falls 30% in a market panic and recovers has not cost a patient owner anything permanent. A stock that falls 30% and then must issue shares at the bottom has.

Common Mistakes

• Chasing the highest possible return without asking what the worst case is.
• Treating a big fall as “only on paper” when the company’s debt could make it permanent.
• Averaging down into a leveraged company without rechecking Criterion 4.
• Letting one winner grow into an oversized position without reviewing its size.
• Using borrowed money to invest. It turns volatility into real risk.

Your Next Step

Check every company you own against the three Criterion 4 tests in how much debt is too much, then look at your largest position and ask whether you could survive it going to zero. For the full background, read what is investment risk.

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About the author: Cameron Hayes is a senior investor relations and finance professional who has worked in IR at Nasdaq Copenhagen-listed companies including Nilfisk and Maersk Drilling. He holds an MSc from Copenhagen Business School and a BCom from the University of Ottawa, and founded Gingernomics to teach individual investors the Five Criteria framework. More about Gingernomics.

The content on Gingernomics is for educational and informational purposes only and does not constitute financial advice. Always do your own research and consult a licensed financial advisor before making any investment decisions. Past performance is not indicative of future results.