Leith van Onselen over at Macrobusiness has written a couple of very important and timely articles on the wealth effect. Put simply, the wealth effect is an increase in spending that accompanies and increase in perceived wealth.
In relation to housing, this paper suggests the wealth effect increases our propensity to consume by 9c per dollar of increased housing value (which is further supported here). So if the housing stock of Australia is valued at $3trillion (some say between 3.5 and 4 trillion), and market values increase 10% in a year, then we will spend on average 9% of the $300billion of new 'wealth', or $27 billion - with $6 billion of spending occurring prior to the end of the next quarter.
Importantly, this money is spent before it is earned by selling the asset. The easy access to home equity lending has been a contributing factor to the size of this effect, enabling households to spend their capital gains before they have been realised which increases their financial risk.
There are few readily available studies about the size of this effect in reverse, but if the same values hold in both directions we can look at some interesting scenarios.
If prices fall 2.5% nationally over a quarter then we lose $75billion of perceived wealth, with an immediate reduction in spending in the following quarter/half year of about $1.5billion and ongoing reductions in spending totalling $7billion
With about $1.7trillion of bank loans outstanding, that is about the same effect on spending as an increase in interest rates of 0.25% and keeping them there for two years (which will mean $4billion extra is spent on interest repayments per year). This of course assumes that house prices are not dramatically affected. Indeed, if we consider that interest rate moves are likely to also bring down home prices, we can expect a much greater effect from the monetary lever.
That’s why house price falls of just a few percent can cascade into a crash so easily.
I would suggest the reason the wealth effect in relation to housing is much higher than found elsewhere is that many people who benefit/lose from house price changes are highly geared, which increases/decreases their equity more quickly for a given price change.
On this note I would add that you can’t directly compare share market volatility to house price volatility, since the share market is an equity market. To make a direct comparison you need to compare the volatility of the equity component of the housing market with share market, or the volatility of the share market value plus the value of debts held by those listed businesses to the housing market.