Anchoring: How Your Purchase Price and the 52-Week High Quietly Steer Decisions

'It was ₹800 last year and now it's ₹400. It has to be cheap.' Variations of this sentence are heard constantly in investing conversations. It sounds like analysis, but it rests on a single comparison: today's price against a past price. The past price is acting as an anchor, a reference point that shapes the judgement even though, by itself, it says very little about what the business is worth now.

Anchoring is one of the most robust findings in decision research. This article explains what it is, the experiments that revealed it, the specific anchors that tend to affect investors, and some practical ways to loosen their grip.

The original experiments

In their 1974 paper 'Judgment under Uncertainty: Heuristics and Biases', published in Science, Amos Tversky and Daniel Kahneman described a striking demonstration. Participants watched a wheel of fortune that was rigged to land on either a low or a high number. They were then asked whether the percentage of African countries in the United Nations was higher or lower than that number, and then to give their own estimate. People who had seen the higher number gave noticeably higher estimates than those who had seen the lower one, even though everyone knew the wheel was random and unrelated to the question.

Tversky and Kahneman called this 'anchoring and adjustment'. People start from an initial value and adjust away from it, but usually not far enough. Later research has found anchoring effects in settings ranging from negotiations to judicial sentencing to price estimates by experienced professionals. If an obviously random number can influence a judgement, a number with apparent meaning, such as a price you personally paid, can be even more powerful.

Common anchors in investing

• Your purchase price. Perhaps the most powerful anchor of all, because it is tied to your own decision and to the feeling of being 'up' or 'down'.
• The 52-week high and low. These figures appear on almost every stock page and quietly frame whether a price looks expensive or cheap.
• The all-time high. After a big fall, people often assume a stock or index will 'get back' to its previous peak, as if the peak were a natural resting point.
• The IPO price. Investors who missed an IPO sometimes compare every later price to the issue price; those who were allotted shares may treat it as a floor.
• Round numbers and milestones. Index levels like NIFTY at a round thousand, or a stock at ₹1,000, attract attention that has more to do with psychology than value.
• Target prices. A single analyst target can become the number against which every subsequent move is judged.

What research found about the 52-week high

In a 2004 paper in The Journal of Finance, Thomas George and Chuan-Yang Hwang studied how a stock's distance from its 52-week high related to its later returns. They found that stocks trading close to their 52-week highs tended, on average, to continue outperforming stocks far from their highs over the following months in the US data they examined. One interpretation they discussed is anchoring: investors may treat the 52-week high as a reference point and be reluctant to bid prices above it even when good news justifies a higher price, so the price adjusts more slowly than it otherwise would.

The specific pattern is a historical, statistical finding about groups of stocks and does not tell you anything about an individual company tomorrow. The broader lesson is that a number many investors are looking at can influence prices simply because so many people use it as a reference.

A worked illustration

Suppose Arjun bought shares of a company at ₹600. Since then, the company has lost a major contract, its debt has risen, and the share price is ₹350. Arjun is reluctant to sell because ₹600 feels like the 'real' value and ₹350 feels like a temporary dip. Meanwhile, his colleague Priya, who has never owned the stock, looks at the same company and sees a business whose prospects have deteriorated.

Both are looking at the same facts. The difference is that Arjun's judgement is being pulled towards ₹600, a number that reflects what the market thought before the bad news, not after it. Neither person is guaranteed to be right about the future. But only one of them is evaluating the company as it is today.

When reference points are legitimately useful

Not every reference point is a trap. Your purchase price matters for calculating tax, for example, and comparing a company's valuation with its own history or with peers can be a reasonable part of analysis. The problem arises when a single number becomes the main reason for a decision, or when it crowds out new information about the business, the economy, or your own needs.

Practical self-checks

• Run the zero-based test: if you held no position and were seeing this company for the first time today, would you buy it at the current price? Write down why.
• Write your investment reason as a thesis about the business, not a price. 'Earnings will grow as capacity comes online' is something you can check; 'it will go back to ₹600' is not a thesis.
• Use more than one lens. Look at valuation relative to earnings, cash flow, and peers rather than relying on distance from a past high.
• Notice when a number is doing the persuading. If the main argument for a decision is 'it was higher before' or 'it's near its low', pause and look for a second, independent reason.
• Separate the tax question from the investment question. Your cost price matters for tax planning, but it should not decide whether the investment still fits your goals.

The takeaway

Numbers you saw first have a surprising hold over judgements that come later. In investing, the most influential anchors are the ones closest to us: what we paid and what the price used to be. Recognising them does not mean ignoring history; it means making sure that history informs the decision rather than making it for you.