Although we may not like to admit it, the past performance of an asset class or fund is likely to have an overwhelming influence on our decision making.  We may try and mask the hold it has on us, but we are inescapably drawn towards investments with strong recent returns. The more pronounced and persistent the outperformance, the greater the pull. There is probably no more prevalent nor puzzling paradox in investing – in order to enhance our returns we make decisions based on a measure that is likely to reduce them.

The past performance of an asset are returns that we are not going to enjoy. They have been (at best) drawn forward from the future – the better the performance before we invest, the worse they will be after. Unusually strong returns are typically the result of unsustainable tailwinds, random doses of good luck and the inescapable swings of market sentiment.

Periods of abnormally strong performance mean that an investment has become more expensive and that it has earned higher returns than it is reasonable to expect on average. Both factors acting as a gravitational pull towards future disappointment.

This type of behaviour is most pronounced in active fund selection. Here it is not even an implicit driver of decision making, but rather an explicit feature of most processes. The popularity of star fund managers is (at least in part) forged on the notion that exceptional returns in the past are a prelude to exceptional returns in the future. We ignore the realities of valuations, the spectre of mean reversion, and fickle hand of fortune, and instead assume that some form of idiosyncratic skill will overcome all of these factors. This is an assumption with terrible odds of success.

The pull of past performance is not unique to fund manager selection, it is pervasive across the industry. We only need to look at the clamour for US equities following a decade (or more) of stellar performance. Investors seem to behave as if the market’s outsized returns in the recent past increase the probability of a continuation of this pattern, when in all likelihood the reverse should be true.

Why do we have such a strong tendency to read the wrong signal from past performance?

Extrapolation: We seemingly cannot avoid believing that trends of the recent past will persist, even when this view seems to be contrary to any rational analysis. A critical part of this anomalous behaviour is the power of storytelling. When assets or funds deliver exceptionally strong (or weak) performance, narratives are weaved to explain them. These compelling stories that justify unusual returns also bolster our belief that they will endure.  

Outcome Bias: Aside from our inescapable short-termism (more on that later), outcome bias is probably the most damaging behavioural foible suffered by investors. Whether it be for a stock, fund or asset class, when we witness strong performance we imbue that thing with some inherent goodness (and vice-versa). High past returns give us increasing confidence in the credentials of an investment. It must be good, haven’t you seen the returns?

Career Risk: For many, being in thrall to past performance is a survival strategy. Most professional investors make decisions to survive over the short-term. Although performance chasing might objectively appear to be an odd strategy at an aggregate level, for an individual it might be the best way to keep our job or avoid another difficult meeting. Investing in the in-vogue areas of the market can be both irrational and rational at the same time – it depends on our objective / incentive.

Instant / Delayed Gratification: Inherent in the paradoxical impact that past performance has on our decision making is the trade-off between instant and delayed gratification. We have an ingrained preference for doing things that make us feel better in the moment over waiting for rewards that may occur at some uncertain future point. Performance chasing gives us an instantaneous, positive hit – we are investing in areas of the market that are working right now, the stories supporting it are captivating and everyone thinks we are making a sensible call. The alternative approach gives us pain now with any benefit someway off in the distance.

One clear signal of the dangers innate in performance chasing is that there is no behavioural cost. It is easy to do and feels good when we do it. Almost all positive investment approaches come with behavioural pain – something has to hurt.

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There is one important exception about the perils of making decisions based on past performance. The success of trend-following strategies, which are explicitly past performance focused. If there is evidence of this working, why is performance chasing such a problem? There is a critical distinction. The success of systematic trend-following strategies is about the consistent application of discipline and rules. Conversely, most investors engage in erratic trend-based investing (we invest in things because they have ‘gone up’) and rationalise the decision based on some post-hoc fundamental analysis.

We are largely secret trend-following investors not admitting how much past performance matters to ourselves or others, and absent the aspects that makes capturing such trends work. 

The paradox inherent in investors’ unhealthy focus on past performance does not mean that we should scour the market for the most egregious laggards, but rather be wary of the influence of high historic returns on our decisions and realistic about its likely consequences. Unusually strong past performance should make us concerned not confident. 

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My first book has been published. The Intelligent Fund Investor explores the beliefs and behaviours that lead investors astray, and shows how we can make better decisions. You can get a copy here (UK) or here (US).