Thursday 21 August 2014

Macro Timing the Stock Market

Many years of stock market investing have proven to me that I am unable to 'pick' individual stocks that will out-perform, and I also can't 'pick' individual funds or fund managers that will consistently out-perform the general stock market (assuming that such funds or fund managers actually exist - there is a body of evidence that suggests that hardly any funds or fund managers 'beat' the relevant index after taking fees into account, and that the few that do are probably the result of random chance rather than intrinsic skill). However, having decided to (mostly) stick with investing in 'the index' (or in the case of our retirement savings, investing in a mix of indexes via the Vanguard 'High Growth' index fund that provides some automatic, low cost, rebalancing  between the various 'growth' indices - Australian shares, International shares, property, bonds etc.) I'm still left wondering if there is some way to 'time' alterations to our investment portfolio. Such as deciding when to be 'fully invested' (or even 'geared' into investments) and when it might be prudent to eliminate gearing or even move partially into 'risk free' investment in fixed interest.

As the stock market is, broadly speaking, a measure of a nation's private wealth-creation, it would seem plausible that the total stock market (eg. the 'all ordinaries' stock market index, XAO) would be correlated to the nations per capita GDP. And, indeed, a plot of this data (obtained from http://www.measuringworth.com/datasets/australiadata/ by selecting the 'Australian Nominal GDP per capita' and 'Australian Stock Index' options for the period 1950 to current) on a logarithmic scale, show that the XAO generally moves in line with the per capita GDP.



What is most interesting is that from this chart it seems quite obvious when the stock market was 'fundamentally' over-valued in the post-WWII period (such as in the late 1960s, in 1987 and in 1999-2001 and again in 2005-2008). The plot suggests that it was a very good idea to reduce leverage/gearing or even to short the market during 2007 to protect against a major correction (my biggest investing cock-up was failing to roll-over my index put options in late 2007), and that at present the Australian stock market isn't particularly over-valued. Indeed 2009 and 2012 look as if the were probably good times to be investing in the Australian stock market.

As I'm already fully invested (and with a bit of gearing into Australian stocks outside of our superannuation investments) the graph doesn't really provide me with much immediately useful information. But such a plot may help 'ring the bell' the next time the stock market is 'expensive' and it is a good time to move my asset allocation towards cash and fixed interest investments. It may also be a good tool for my sons to use when managing their investment asset allocation over the coming decades....

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1 comment:

David Stern said...

Interesting graph. I'm surprised how close the two fit and overall there hasn't been a "deepening" or the reverse in terms of the stock market capitalization relevant to economic activity. I wonder if the story it tells is any different than just looking at the P/E ratio? The potential problem with P/E is it is sensitive to interest rates. So maybe this works better. I don't know where to get a long history of P/E ratios for Australia either.