The Disposition Effect

A person who has not made peace with his losses is likely to accept gambles that would be unacceptable to him otherwise.

(Kahneman and Tversky, 1979) 

Stock brokers prefer to sell stocks that rise in price than stocks that fall in price. The preference for 'winners' over 'losers' is driven only by the desire to realise gains over losses. This is called the disposition effect, and it is likely to lead to lower profits.

This is because attitude to risk is different for losses than gains. Behavioural economics has shown that people tend to be risk seeking when it comes to losses, but risk averse when it comes to gains. For example, a stock that depreciates in value will be seen as a loss, making the stock broker more risk seeking and therefore more likely not to sell it (it may go up in value again). But if the stock rises in value then the stock broker is more risk averse and therefore more likely to sell it (to avoid the risk of it falling in value).

The disposition effect increases taxable income (Odean, 1998). If stock brokers realise 'winners' they have to pay tax on the gain. But stock brokers do not have to pay tax on 'losers'. Thus stock brokers could put off paying tax (and thus earn money) by holding 'winners' for longer. And by selling 'losers' taxable income reduces; if stock brokers sell the 'losers' and buy almost identical stocks taxable income actually falls. Thus the disposition effect is irrational for stock brokers (but good for the Inland Revenue!).

The disposition effect is a violation of fungibility because investors view units of money either side of the gain/loss boundary as qualitatively different. This is an example of non-fungibility causing market failure. If investors were aware of this non-fungibility they might be less likely to exhibit it.

Putting the Fun into Fungibility

My apologies for my recent silence, I've been working hard on my MSc dissertation (now successfully finished). The topic of my dissertation was 'fungibility'. My next few posts will explore fungibility and why being aware of it may help you make more rational decisions.

Fungibility is the principle whereby economic agents treat all units of money as equal and as perfect
substitutes, regardless of where they came from.

Violations of fungibility occur when individuals use money differently because of the way it was earned, stored or labelled. Violations of fungibility can cause us to make suboptimal decisions and are thus termed irrational.

Take the example of an €8 gift voucher at an expensive restaurant. For some customers the voucher can be spent on beverages (the 'labelled' voucher) while for others the voucher can be spent on either food or beverages (the 'unlabelled' voucher). As almost all customers spend at least €8 on beverages the gift is 'nondistortionary'.

Johannes Abeler and Felix Marklein (2013) ran this field experiment and found that customers who had the labelled voucher spent on average €3.90 more on beverages than those with the unlabelled voucher.

The label attached to the money had changed behaviour (even though, rationally speaking, both groups should have spent the same amount on beverages as the voucher was nondistortionary). This 'labelling effect' violates the principle of fungibility.

So the next time you receive a labelled voucher think to yourself 'Would I have spent that much on ... anyway?' 'How much was I originally prepared to spend on ...?'

It might just help you avoid be more rational in how you spend your money.

Air Regulation

A recent paper by two economists (Aguirregabiria and Ho) caught my eye.

Typically, in America, airlines operate 'hub and spoke' networks. That is, an airline will have a main airport (the hub) and all the other cities in the network (the spokes) only fly to the hub. Why do airlines tend to do this?

There are three main possibilities that the paper explores:

1. Passengers prefer large airports which tend to be more efficient, so are prepared to fly via the hub airport.
2. Airlines benefit from lower running costs (economies of scale) at a hub airport.
3. Airlines find it easier to deter competition by operating out of a hub airport.

Aguirregabiria and Ho find that airlines do benefit from costs savings of a hub airport. But they also find that airlines running a hub and spoke network tend to run more loss making services. They interpret this as a way of large airlines stopping smaller competitors from starting to run those 'spokes'. They also find that by having a hub airport an airline can drive up the cost of other airlines running services to that particular airport.

Thus hub and spoke networks could be a way airlines deter competition. 

If proven, air industry regulators should look into how airlines manage their networks and whether they illegally deterring competition that would benefit passengers.

Who Are We Really?

Behavioural economics finds it's significance from the way it reframes the economic perspective of human beings. We are no longer simply called homo economicus. We are allowed to selfless, confused and cooperative.

But that is not entirely satisfactory. The economic paradigm is still in place. We are still primarily consumers. We exist to consume, and consume to exist. We may occasionally give some of our consumption to others, but our primary purpose is unchanged.

There are, as I see it, two main drivers of this consumption complex. Our philosophical leaders (economists and their mindless followers; politicians) who tell us that consumption is everything. And us, who seemingly have an innate drive to get more stuff. More stuff than we had yesterday, more stuff than our neighbours have today.

The problem is that consumption isn't everything. We are more complex than that. Happiness is not just a function of consumption (c.f. friends, family). We cannot be reduced to one-dimensional, consuming robots.

And if that were not enough to make us think twice, limitless consumption is not actually achievable. Our environment has limits. The planet has limits. There are only so many fish in the sea. As Stewart Wallis (of the think tank the new economics foundation) recently said in a TED talk, we need to move on from seeing ourselves as consumers to stewards. Based purely on pragmatism, a serious change in our self-image is needed.