Projecting Market Returns


Market prognosticators frequently opine in the direction of the markets based on public policy, what Millennials are doing, whether Euro will do this and the Yen will do that, who won the Super Bowl, if it is an election year, etc.  They have no idea what they are talking about.

The more accurate forecast models take a hard look at value.

Shiller P/E

One method is the Shriller P/E.  It was designed by Yale economist Robert Shiller.

Looking at the market in terms of the current P/E can be misleading depending on where we are in the business cycle.  For instance, during a recession, earnings plummet and P/E ratios rise even though the market may be undervalued.   During a boom, earnings are temporarily inflated, which can cause the market to appear cheap when it may in fact be quite expensive.  Shiller accounted for this by comparing price to average earnings over the last 10 years, accounting for the impact of economic gyrations.

Gurufocus maintains a nice  tracker of the Shiller P/E here.

Market Capitalization as Percentage of GDP

A better method is looking at the market in terms of its value in relation to GDP.  Buffett popularized this method in a 1999 article in Fortune.  Buffett was able to use market valuation as a percent of GDP to assess market values.  He assessed the market correctly at the time and declared the market to be overvalued.

The methodology is easy to understand.  The market derives its value from earnings and US companies can only earn what the US economy can actually produce.

Gurufocus maintains a tracker for this metric here.

A Better Method

The GDP method is more accurate than the Shiller PE, but it is still an imprecise instrument.  For instance, the GDP model predicts a range of returns over the next 10 years of +4.6% to -8.2%.

Recently I came across a market valuation model that was even more compelling at the Philosophical Economics blog.  This model instead looks at the average equity allocation.  The idea is that during a bull market, valuations increase as investors move their money from other asset classes into stocks.  As the equity allocation increases, the market runs out of fuel for higher valuations and future returns are diminished.

The key reason this makes sense is the relationship between interest rates and returns.  As interest rates rise, it seems natural that investors would decrease their equity allocation and put more of their funds towards bonds.  If bonds are dishing out high rates of return for little risk, why take the risk of owning equities?  This is precisely what happened in the 1970s and early 1980s, when interest rates soared and equities were punished.  It also set the stage for an extraordinary period from 1982 to 2000, in which declining interest rates from historic highs fueled one of the greatest bull markets in history.

Interestingly, as Buffett pointed out in the earlier referenced 1999 article, earnings and economic growth were actually less in the 1980s and 1990s than they were in the 1960s and 1970s.  The only difference between the two periods is the direction of interest rates.

The model can actually be plugged into a simple equation:

Expected 10 year rate of return = (-.8 * Average Equity Allocation)+37.5

Looking at the most recent data, the current average equity allocation is 40%.  Plug this into the equation and we get the following result: (-.8 * 40) + 37.5 = 5.5% expected 10 year rate of return

The metric is tracked here and is updated quarterly.  If the equity allocation were to rise to 45%, that implies that the next ten years will deliver a paltry 1.5% return.  That would hardly seem sufficient compensation for the volatility risk in equities.

So What?

Generally I like to remain agnostic about the market and focus on bargain stocks.  However, my 401(k) plan is dedicated to index funds and I think it makes sense to look at market valuations.  An overvalued market combined with an overheating economy is certainly cause for concern and something investors should remain cognizant of.


They heard that the average equity allocation went down in the most recent quarter

The model described in this post should reduce your fears when the market drops.  A market drop simply means that future returns are going to be higher.  Drops in the market are cause for celebration, as you can now buy stocks that will deliver a higher rate of return.  I would certainly buy more if the market were to plunge 50% tomorrow.  I’d also probably start scrounging whatever cash I had on hand and piling into the market.

PLEASE NOTE: The information provided on this site is not financial advice and I am not a financial professional. I am an amateur and the purpose of this site is to simply monitor my successes and failures.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s