Anchoring and Adjustment is a powerful Cognitive Bias and mental shortcut (a `Heuristic`) that describes our tendency to rely too heavily on the first piece of information we receive—the “anchor”—when making decisions. First described by the psychologists Daniel Kahneman and Amos Tversky, this bias shows that once an anchor is set in our minds, we rarely adjust our estimates far enough away from it, even in the face of new, contradictory information. Imagine someone asks you to guess the percentage of African nations in the UN. But first, they spin a “wheel of fortune” that lands on either 10 or 65. Those who see the number 10 guess a much lower percentage than those who see 65. The initial number, though completely random, has anchored their judgment. In the world of investing, this bias can be a portfolio's worst enemy, tethering your decisions to irrelevant numbers rather than to a company's true worth.
For investors, anchors are everywhere, and they can be dangerously persuasive. They create a psychological benchmark that can distort your perception of value and lead to irrational choices that are completely at odds with a sound Value Investing strategy. Recognizing these anchors is the first step toward freeing yourself from their influence.
This is perhaps the most common and destructive anchor for the average investor. When you buy a stock at $100, that price becomes a powerful mental anchor.
Every financial website and trading app displays a stock's 52-week price range. This readily available data point is a notoriously misleading anchor. A stock trading near its 52-week low is not automatically “cheap,” and one near its 52-week high is not automatically “expensive.” A business's value can change dramatically over a year. A low price may reflect a truly broken business, while a high price might still be a bargain if the company's growth has been spectacular. Anchoring to these arbitrary highs and lows is a substitute for the real work of valuation.
The very first piece of data you encounter about a potential investment can set an anchor for your entire analysis. This could be:
Once this initial number is lodged in your brain, it can be difficult to assess new information objectively. This is often magnified by Confirmation Bias, where you subconsciously start looking for reasons to justify your initial, anchored impression.
The good news is that while anchoring is a natural human tendency, it can be overcome with discipline and a structured process. A value investor's primary defense is a relentless focus on business value over market noise.