You know less precisely than you feel you do, and the first number you saw is still quietly steering the decision you think you are making freshly.
9 min read · Level 1
The purchase price is the single most contaminating number in an investor's head, and the hardest one to put down, because letting go of it means admitting that a decision you made is not going to be vindicated. Nothing in the market is working towards getting you back to even - there is no force pushing a price towards what one particular person paid for it. An investor who can genuinely evaluate a position as though they had inherited it that morning has removed the largest single source of avoidable error in their process.
Overconfidence in investing is mostly not about thinking you are brilliant. It is about ranges being too narrow: when people estimate a figure and give a range they are 90% sure contains the answer, the true value falls outside that range far more often than one time in ten. The confidence is in the precision, not the ego, which is why modest people are just as prone to it.
Anchoring is the pull exerted by a number you have already seen - usually the price you paid, sometimes the highest price it ever reached, sometimes the valuation someone first mentioned. That number has no bearing on what the thing is worth now, but it reliably becomes the reference point against which every later judgement is made.
Because these two combine into a specific, expensive behaviour: refusing to sell something at a loss because the price you paid feels like the price it 'should' return to, while being certain that your estimate of its true value is more precise than it is. The market does not know what you paid. The only question that matters is whether you would buy it today at today's price, and anchoring is what makes that question feel unfair rather than obvious.
This is educational information, not investment, securities or financial advice. Rules differ by country and change — get advice from a qualified professional in your jurisdiction before acting.
Educational, not personalised financial advice. Nothing in the Investor Academy is a recommendation to buy, sell or hold anything — what is right for you depends on your own circumstances and the rules where you live.
Sources: U.S. SEC — Investor.gov; CFA Institute
You bought at 40 and it now trades at 22 - a fall of 45%. The anchored question is 'when does it get back to 40?', which needs a rise of 81.8% from here. The unanchored question is simply: at 22, given everything known today, is this the best place for that money? Those two questions often have different answers, and only the second one is answerable. Notice also how the arithmetic punishes the wait: getting back to even requires a much larger percentage gain than the percentage loss that created the hole, and the deeper the hole the worse the asymmetry - a 50% fall needs a 100% rise, an 80% fall needs 400%.
Holding a losing position specifically because selling would make the loss 'real'. The loss is already real; selling only changes where the money sits. This is the sunk-cost fallacy wearing investment clothing, and it is strengthened by the fact that the original purchase was your decision - letting go of the position means letting go of the story in which that decision was correct.
When you estimate anything - a growth rate, a valuation, a timeline - take your range and widen it until it feels slightly silly. That is roughly where a well-calibrated range starts.
For any holding, ask whether you would buy it today at today's price with fresh money. If the answer is no and the only reason to hold is what you paid, you are being steered by an anchor.
Write your predictions down with dates. Calibration only improves if you can later see how often reality landed outside the range you were sure about.
In a negotiation, a fundraise or a listed price, the first figure mentioned is a position, not a valuation. Do your own work before reacting to it.
Whenever you are deciding whether to hold, add to, or exit a position that has moved significantly in either direction from where you bought it.
Purchase price does legitimately matter for tax reporting and for measuring your own results. The rule is that it must not enter the decision about what the asset is worth now - not that it never matters at all.
A tendency among individual investors to realise gains more readily than losses has been documented repeatedly in academic studies of brokerage records across several countries and decades. The behaviour is consistent enough to have its own name in the literature - the disposition effect - and it holds even where the tax treatment of the two actions argues for the opposite.
The pull is strong enough to overcome a financial incentive pointing the other way, which is a useful measure of how little willpower alone is going to achieve here.
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