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The Theorem of Modest Greed

If a £500 note were lying on the pavement, someone would already have picked it up

Problem it solves

Falling for get-rich-quick schemes through failure to apply basic market logic

Best for

Evaluating any investment offer, business scheme, or 'opportunity' that promises unusually high returns

Not ideal for

Evaluating genuinely novel early-stage opportunities where no market has yet formed

Overview

Why this framework exists

Economists de Mosy's Theorem of Modest Greed states a simple but devastatingly effective heuristic: you do not find £500 notes on the pavement. If one were there, someone would have picked it up. The logic transfers directly to investments, business opportunities, and get-rich-quick schemes: if an opportunity to make exceptional risk-free returns genuinely existed, other market participants with capital and information would already have exploited it — and in doing so, eliminated the opportunity.

This is the economic argument against virtually every get-rich-quick scheme: drop-shipping, certain crypto plays, 'passive income' courses, and leveraged schemes all follow the same logical structure. If the scheme worked as advertised, the person selling it would be doing it — not selling you a course about it for £997. The fact that they are selling you the course is direct evidence that the underlying opportunity has either closed, never existed, or is not what they claim.

Angner extends the argument to survivorship bias in business and investing narratives. The person on television explaining how they got rich from Bitcoin, drop-shipping, or a niche investment product took advantage of an opportunity that no longer exists. Their story is true but not replicable — because replication would require the same conditions at the same time, which you cannot access now. You are being shown the winner of a lottery and asked to buy the same ticket retroactively.

Core principles

5 total
  1. Genuinely exploitable market inefficiencies are eliminated the moment they are discovered by anyone with capital.
  2. Anyone selling you a method to get rich is providing direct evidence that the method no longer works at scale.
  3. Survivor bias means you only hear from the winners — the thousands of failures are invisible.
  4. Business school narratives are not representative: they select for exceptional outcomes, not typical ones.
  5. The correct comparison class is everyone who was once in the same situation, not the one person who succeeded.

Steps

4 steps
  1. Apply the pavement test
    Ask: if this opportunity were as good as claimed, why isn't everyone doing it? If the answer is 'most people don't know about it yet,' follow up: how did you find out, and why hasn't capital already flooded in?
    Pro tipThe more novel and obscure the opportunity sounds, the more vigorously you should apply this test.
  2. Ask why the seller is selling
    If the person promoting the scheme has genuinely found a reliable way to generate exceptional returns, they should be deploying capital — not selling you a course. The act of selling courses about an opportunity is strong evidence the underlying opportunity has closed.
    Pro tipThis test catches most internet schemes instantly. If the money is in the course, not the strategy, the strategy does not work.
  3. Find the failure rate, not just the success stories
    For any strategy or business model, find everyone who tried it, not just the one person presenting it. Drop-shipping, YouTube channels, property investment, day trading — all have visible success stories and largely invisible failure rates.
    Pro tipAcademic meta-analyses exist for most common investment strategies. They are far more informative than any individual's testimonial.
    WarningBusiness school case studies are selected for exceptional outcomes. They are the worst possible sample for making typical investment decisions.
  4. Check whether the conditions that produced the win still exist
    Even genuine success stories often depend on timing-specific conditions that no longer obtain. Damian's YouTube channel succeeded partly due to a global pandemic creating enormous demand for financial content. That window is closed.
    WarningThe question is never 'did this work for someone?' but 'does this opportunity exist for me, now, given current conditions?'

Checklist

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Examples

3 cases
The drop-shipping pitch

Someone in the episode's discussion describes drop-shipping schemes: 'you just be the middleman, order for someone and then deliver it somewhere else, you can make loads of money.' The pitch is that most people don't know about it yet.

OutcomeAngner's response: 'If it was that easy everyone will be doing it.' The logic of the theorem applies — if the opportunity were real at that scale, capital would have eliminated the margin. The £500 would already be gone.
Bitcoin retrospective advice

After-the-fact advice to invest in Bitcoin is presented as proof of the strategy. The people who made extraordinary gains from Bitcoin in early years are highly visible; the majority who bought at the wrong time are not.

OutcomeSurvivor bias. The opportunity existed at a specific moment for people with specific information and risk tolerance. The advise to 'invest in Bitcoin like that guy did' assumes conditions that no longer exist.
Damian's YouTube channel

Damian offers a self-deprecating account of his own success: he started a finance channel during a global pandemic, worked 100-hour weeks for four years, and is 'one of five' from his cohort still standing.

OutcomeIllustrates the theorem from the positive side: the conditions that produced his success (a pandemic driving demand for financial content, extreme effort, survivorship from a large pool of entrants) cannot be packaged and sold as a replicable strategy. 'I can't bottle that.'

Common mistakes

4 traps
Treating compelling narratives as replicable strategies
A vivid story of someone who got rich activates System 1 thinking and makes the outcome feel likely. But narrative quality is independent of representativeness. The most compelling stories are usually the least typical.
Confusing the lottery winner with the lottery strategy
After the fact, every lottery winner can explain which ticket they bought. This is not investment advice — it is survivor reporting. The strategy (buy ticket X) has already been exhausted for everyone who did not buy it in advance.
Ignoring the seller's incentive structure
Course sellers, YouTube gurus, and certain financial advisers make money from the course or the assets under management — not from deploying the strategy. This misalignment is a reliable signal that the strategy does not work as advertised.
Mistaking novelty for opportunity
New technologies (blockchain, AI, drop-shipping) attract schemes dressed in novel language. The theorem applies regardless of the wrapper — if the return is exceptional and easily accessible, it should already have been arbitraged away.

Origin story

How this framework came to be

Angner attributes the theorem to economist de Mosy and encountered it in the academic economics literature on market efficiency. He presents it not as an abstract theorem but as a practical filter for the daily noise of get-rich schemes that arrive via email, YouTube ads, and business school case studies. His framing — 'if you found £500 on the floor you wouldn't go to a guy and go give me 20 quid I'll show you where there's £500 on the floor every day' — makes the logic viscerally obvious.

Source

Traced to primary
Source · PODCAST
The Economist's Guide To Getting Rich
Erik Angner · 2025
Open source →

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