top of page

5 biases that will hinder your investment journey

I’ve been reading (actually listening to, via the wonderful Audible app) a wonderful book called Thinking, Fast and Slow by the Nobel prize winner Daniel Kahneman.

Daniel Kahneman is an Israeli-American psychologist and economist notable for his work on the psychology of judgment and decision-making, as well as behavioural economics, for which he was awarded the 2002 Nobel Memorial Prize in Economic Sciences.

Behavioural economics has revealed many ways that investors — and investment advisers — can make mistakes or be fooled by things that are not what they seem.

In his book, Daniel writes about a long list of biases and errors that can undermine our best intentions. I wanted to look at the five main areas I think are most relevant for us to watch out for within our investment journey.

1. Overconfidence

Very few people are what Kahneman calls ‘well-calibrated’ when it comes to their confidence in their predictions, even when it is in their interest to make an accurate forecast.

He suggests that when someone says they are 99% confident, it should be assumed that the real probability is 85% (or less).

You also see the overconfidence bias at work when you ask people about how good they are at driving, compared to others. 80% of drivers believe they are ‘above average’.

Adding optimism to overconfidence produces a powerful compound effect. Optimism leads people to underestimate the possibility of bad outcomes while overestimating the possibility of positive outcomes.

2. Hindsight bias

People are very bad at recalling after an event, what they believed before it. Kahneman’s example is to try and recall what you thought the probability of the last central bank action was the day before it occurred.

Most people can’t reconstruct their prior belief after the event, so many are honestly deceived when they exaggerate their earlier estimate of the probability that the event would occur.

At other times, the hindsight bias manifests as totally unexpected events appearing virtually inevitable after the fact.

Kahneman warns that this bias poses a particular threat for financial advisers, as hindsight can ‘… turn reasonable gambles into foolish mistakes in the minds of investors’. After a stock has fallen, he explains, its fall appears to have been inevitable – so why didn’t the adviser suggest selling it earlier?

3. Overreaction to Chance Events

Humans are pattern-seeking creatures and we can be easily fooled by finding them where they do not actually exist!

Kahneman considers two coin-toss sequences of heads (H) or tails (T):



Most people consider the random pattern in option 2 to be more likely to occur than the apparently systemised pattern in option 1.

In reality, the probability is identical for both sequences.

In finance, people often see trends where none exist and end up taking actions based on an erroneous impression.

One study analysed hundreds of thousands of share trades and found that where people sold one stock and quickly bought another, the stock they sold outperformed the stock they bought by 3.4% in the first year.

4. Purchase price reference point

Investor A owns a share they bought for £100, while investor B owns the same share but paid £200. Yesterday the share-price was £160 — today it is £150. Is person A or person B more upset?

Kahneman’s research discovered that people ‘feel’ the pain of losses more than the pleasure of gains, so investor B is feeling the most hurt. Their loss is increasing, while investor A has only suffered a reduction in gains.

Being anchored to a purchase price underpins the disposition effect, where an investor sells a stock that has gone up but keeps the one that has fallen.

5. Regret and risk-taking

Most people feel more regret about things that they did do than things they did not do. But one study has shown that people who regret investment opportunities they missed tend to take more subsequent risks than people who regret attempts that failed.

Risk-takers were also found to downplay the role of luck in both positive and negative outcomes, believing their judgment played a more important role.

What biases mean for your investment journey

Understanding our biases is vital to having a successful investment journey which will then lead onto us having the freedom and peace of mind to have an extraordinary retirement.

Our four core investment beliefs are purposely designed to stick to the evidence and allow us to avoid suffering from any of the above (and more) biases. They are:

  1. Goals – Only invest based on a lifetime financial plan

  2. Diversification – Globally diversify your holdings and get the balance of equities and bonds right for you

  3. Cost – Costs of all kinds really matter, and the number one predictor of underperformance is high costs. We look to minimise all costs.

  4. Discipline – Stay invested; ignore the noise

If you want to create a financial plan that works for you, please get in touch. Email or call us on 01621 851563.


bottom of page