One area of weakness is our poor grasp of the exponential impact of compounding that can work both for and against us.
Imagine three different portfolios that deliver returns of 1%, 3% and 5% per year after inflation, but before other costs, over a period of 30 years: £100,000 invested in each would result in a growth of purchasing power to around £135,000, £240,000 and £430,000 respectively. Seemingly small differences in the compound rates of return (geometric returns), turn into large differences, in terms of financial outcomes. That’s one of the great positives of a disciplined and patient approach to investing – small returns turn into big numbers, given time.
On the other side of the coin, costs – when compounded over time – eat away at these market returns to a far greater degree than many investors ever imagine. Let’s compare two managers who deliver 3% gross (before fees) above inflation, where Manager A has costs of 0.25% and Manager B has costs of 1.00%. We plot the purchasing power impact of these different fee strategies on outcomes, across time, in the chart above. As you can see, costs matter a great deal; an investor in Manager B’s fund is over £40,000 worse off than an investor with Manager A’s fund over 30 years. Put another way, you end up one third more wealthy selecting Manager A over Manager B.
To read more on this subject, take a look at Acuity Volume 47: How to get what you don't pay for.