Unimaginable-Risk Margin
Hold more slack than forecasts justify so surprises cannot force you out.
- Difficulty
- Moderate
- Time to result
- ~months to results
- Steps
- 4
- Confidence
- 99%
The Unimaginable-Risk Margin treats forecasts as incomplete by construction. Planning begins with known threats, but then deliberately adds financial slack for events that have no place in the forecast. Housel argues that the greatest disruptions—such as COVID-19, September 11, or Lehman Brothers failing—were largely missing from conventional investor outlooks. Therefore, a portfolio designed only around named scenarios is fragile. The practical response is a level of savings or conservatism that may look slightly excessive in ordinary times. That apparent inefficiency is the signal that the plan may cover surprises as well as expectations. The margin is successful when an unforeseen event does not force the person to sell long-term assets, abandon the plan, or become insolvent.
Origin
Extracted from The Tim Ferriss Show
Core principles
- 01The largest risks are often absent from forecasts.
- 02Preparing only for imaginable events leaves the biggest gap open.
- 03Useful conservatism can look excessive before a crisis.
- 04Slack preserves the ability to stay in the game.
How to run it
- 1
Audit the forecast
Identify which risks the current plan explicitly anticipates and how it responds to each one.
Watch out A long risk list can create false confidence that it is complete.
- 2
Reserve for the unnamed
Add savings, liquidity, or reduced exposure beyond what the named scenarios require.
Pro tip The reserve should feel somewhat conservative during normal conditions.
Watch out Do not assign the entire margin to a new forecast and call the uncertainty solved.
- 3
Test forced-exit paths
Ask whether a surprise could require selling at a loss, taking ruinous debt, or leaving the game.
Pro tip Focus on irreversible consequences rather than temporary discomfort.
Watch out A plan that survives only if markets cooperate has no true margin.
- 4
Preserve the buffer
Maintain the margin even when calm periods make it appear wasteful.
Pro tip Evaluate the buffer by the failures it prevents, not only its quoted yield.
Watch out Optimism late in a cycle can quietly consume the protection.
In the wild
Ferriss read Housel's example in which cash earns less than stocks but prevents an investor from selling stocks during a bear market. Its practical return can therefore be many multiples of its stated interest rate.
→ Low-yield liquidity protects the higher-return strategy by preventing a forced exit.
Common mistakes
Planning only for named risks
The event that matters most may be the one that never appeared in the plan.
Optimizing away all slack
A perfectly efficient allocation can become brittle when reality differs from the spreadsheet.
Is it for you?
Best for
It is best for households and investors whose long-term success depends on surviving rare disruptions.
Not ideal for
It is not ideal when excessive reserves would prevent meeting a near-term essential obligation.
From the transcript
“risk is what is left over when you think you've thought of everything”
“you have to have a level of savings in your asset allocation that doesn't make sense”
“you have to have a level of conservatism that seems like it's a little bit too much”
From the episode
#576: Morgan Housel — The Psychology of Money, Picking the Right Game, and the $6 Million Janitor
Morgan Housel