Uncertainty & Prediction
The foundational acknowledgment that the macro future is unknowable — that economic forecasting is unreliable — and that the appropriate response is preparation over prediction, building portfolios that survive a range of outcomes rather than optimizing for a single forecast.
“The most important thing isn't predicting the future — it's understanding that nobody can predict it reliably, and investing accordingly.”
“You can't predict; you can prepare.”
Concept Analysis
Definition & Origins
The foundational acknowledgment that the macro future is unknowable — that economic forecasting is unreliable — and that the appropriate response is preparation over prediction, building portfolios that survive a range of outcomes rather than optimizing for a single forecast.
Marks' engagement with uncertainty begins with his credit analyst training: the question of whether a borrower will repay is irreducibly probabilistic, not deterministic. This is different from equity analysis, where the standard framework often treats the future as knowable. Credit analysis forces honest engagement with what cannot be known.
The 'Nobody Knows' memo (2001) was written immediately after September 11 — a quintessential black swan event that no forecaster had predicted. The impossible-to-predict character of that event became the template for Marks' general argument: if a macro outcome of that magnitude is unforeseeable, what does that imply about the reliability of any macro forecast?
Core Ideas
The future is genuinely unknowable, not merely unknown. Marks distinguishes between 'unknown' (information that exists and could be discovered) and 'unknowable' (outcomes that have genuine randomness or are causally undetermined). Most macro events are in the second category. The Federal Reserve's next decision is unknown but exists in someone's mind; the outcome of a geopolitical confrontation is genuinely unknowable because it depends on many actors' decisions made in response to each other's actions.
Forecasting has no demonstrated value in aggregate. Despite the enormous investment of time, money, and talent in macroeconomic forecasting, there is no convincing evidence that forecasters, as a group, outperform simple extrapolation over multi-period horizons. The illusion of forecasting skill is maintained by selective recall of hits, adjustment after the fact, and the persistence of people who were right once.
Macro-agnosticism is not passivity — it is a positive repositioning toward what is knowable. Marks is not arguing that investors should be passive or indifferent to the macro environment. He is arguing that capital allocation should be based on what is genuinely analyzable: security-level fundamentals, credit quality, valuation relative to intrinsic value, cycle position in terms of sentiment and supply/demand — not on macro forecasts.
You can prepare for a range of outcomes without predicting any one of them. Portfolio construction under uncertainty requires asking: what scenarios are plausible, how would this portfolio perform under each, and is the aggregate risk/return profile acceptable? This is different from optimizing for a single forecast. A portfolio that survives the 1-in-10 bad scenario while participating in the 7-in-10 good scenarios is better designed than one that maximizes the good scenario and fails catastrophically in the bad one.
The appropriate response to uncertainty is humility about one's own process. Uncertainty doesn't just apply to the external world — it applies to the investor's own analysis. Even within the domain of credit analysis where Marks operates, forecasts of recovery rates, restructuring outcomes, and business recovery are uncertain. The correct response is wider margins of safety, more conservative assumptions, and more explicit scenario analysis.
Practical Application
Nobody Knows (2001): The September 11 memo argued that in a moment of genuine macro uncertainty, the appropriate portfolio posture is not to bet on an outcome but to ask what prices imply about outcomes and whether those implications are more or less pessimistic than warranted. After September 11, prices implied extreme pessimism — which meant expected return was high for someone willing to provide liquidity.
Nobody Knows II (2020): The COVID version made the same argument in a faster-moving scenario: prediction about COVID's trajectory was impossible in February 2020. Marks did not predict recovery. He argued that at the depth of the market fall, pessimism had been priced in aggressively enough that the risk/return ratio was attractive even without knowing the trajectory.
The Sea Change memos (2022–2025): The regime change of 2022 is itself an argument from uncertainty: Marks does not claim to know where interest rates will go. He claims that the world has changed enough that the assumption of 'rates return to zero' — which many portfolios implicitly rely on — is no longer tenable. The appropriate response is not to forecast rates but to reduce the portfolio's dependence on any single rate environment.
Common Misconceptions
Misconception 1: If you can't forecast, you can't invest This is the error of treating uncertainty as a barrier rather than a permanent condition. Every investor operates under uncertainty. The question is whether you acknowledge it explicitly (and build portfolios accordingly) or pretend it doesn't exist (and build portfolios that are catastrophically fragile to the outcomes you haven't modeled).
Misconception 2: Confidence is a virtue in investing Social and institutional contexts reward confident forecasts. 'I don't know' is interpreted as weakness. But epistemic humility is not the same as analytical weakness — it is an accurate description of the state of knowledge about the macro future. The investors who communicate false confidence about macro outcomes are not smarter; they are more willing to mislead.
Howard Marks' Own Words
"You can't predict. You can prepare."
"There are two types of forecasters: those who don't know what the future holds, and those who don't know that they don't know."
"Nobody knows the future. The strange thing is how confident people sound when they describe it."
"An investor who says 'I don't know' is not being cowardly. He is being honest. And honesty about what you don't know is the beginning of wisdom about what you do know."
Thought Evolution
Related Concepts
Key Memos
First systematic argument that macro forecasting is unreliable and portfolio construction should reflect epistemic humility
COVID-era update; uncertainty during an unprecedented pandemic event
Epistemological analysis of why investors believe they know things they don't
The nature of prediction in complex systems
Latest iteration; AI, tariffs, and the permanent limits of forecasting