Bonds: Reversion Cuts Both Ways

Robert Arnott, Founder, Research Affiliates, and innovator of FTSE-RAFI Fundamental Indices, has published a detailed report testing the question of why investors should bother holding bonds (at all?) and displacing the long-standing notion that stocks for the long run hold a 5-percent risk premium over bonds. This is a must-read-over-the-weekend report as it is lengthy, but far from boring.

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"Reversion cuts both ways," according to Arnott.

For four decades, from time to time, we hear this question: Why bother with bonds at all? Bond skeptics generally point out that stocks have beaten bonds by 5 percentage points a year for many decades, and that stock returns mean-revert, so that the true long-term investor enjoys that higher return with little additional risks in 20-year and longer annualized returns.

Recent events provide a powerful reminder that the risk premium is unreliable and that mean reversion cuts both ways; indeed, those 5 percent excess returns, earned in the auspicious circumstances of rising price-to-earnings ratios and rising bond yields, are a fast-fading memory, to which too many investors cling, in the face of starkly contradictory evidence. Most observers, whether bond skeptics or advocates, would be shocked to learn that the 40-year excess return for stocks, relative to holding and rolling ordinary 20-year Treasury bonds, is not even zero.

The Death Of The Risk Premium?

It’s now well-known that stocks have produced negative returns for just over a decade. Real returns for capitalization-weighted U.S. indexes, like the S&P 500 Index, are now negative over any span starting 1997 or later. People fret about our “lost decade” for stocks, with good reason, but they underestimate the carnage. Even this simple real return analysis ignores our opportunity cost. Starting any time we choose from 1979 through 2008, the investor in 20-year Treasuries (consistently rolling to the nearest 20-year bond and reinvesting income) beats the S&P 500 investor. In fact, from the end of February 1969 through February 2009, despite the grim bond collapse of the 1970s, our 20-year bond investors win by a nose. We’re now looking at a lost 40 years!

Stocks have done better, but not in the last 40 years...

It’s hard to imagine that bonds could ever have outpaced stocks for 40 years, but there is precedent. Figure 1 shows the wealth of a stock investor, relative to a bond investor. From 1802 to February 2009, the line rises nearly 150-fold. This doesn’t mean that the stock investor profited 150-fold over the past 200 years. Stocks actually did far better than that, giving us about 4 million times our money in 207 years. But bonds gave us 27,000 times our money over the same span. So, the investor holding a broad U.S. stock market portfolio was 150 times wealthier than an investor holding U.S. bonds over this 207-year span. So far, so good.

That 150-fold relative wealth works out to a 2.5-percentage-point-per-year advantage for the stock market investor, almost exactly matching the historical average ex ante expected risk premium that Peter Bernstein and I derived in 2002 in “What Risk Premium Is ‘Normal’?” Those who expect a 5 percent risk premium from their stock market investments, relative to bonds, either haven’t studied enough market history—a charitable interpretation—or have forgotten some basic arithmetic—a less charitable view.

A 2.5 percentage point advantage over two centuries compounds mightily over time. But it’s a thin enough differential that it gives us a heck of a ride.

• From 1803 to 1857, stocks floundered, giving the equity investor one-third of the wealth of the bond holder; by 1871, that shortfall was finally recovered. Oh, by the way, there was a bit of a war—or three—in between. Forget relative wealth if you owned Confederate States of America stocks or bonds. Most observers would be shocked to learn that there was ever a 68-year span with no excess return for stocks over bonds.
• Stocks continued their bumpy ride, delivering impressive returns for investors, over and above the returns available in bonds, from 1857 until 1929. This 72-year span was long enough to lull new generations of investors into wondering “why bother with bonds?” Which brings us to 1929.
• The crash of 1929–32 reminded us, once again, that stocks can hurt us, especially if our starting point involves dividend yields of less than 3 percent and P/E ratios north of 20x. It took 20 years for the stock market investor to loft past the bond investor again, and to achieve new relative-wealth peaks.
• Then again, between 1932 and 2000, we experienced another 68-year span in which stocks beat bonds reasonably relentlessly, and we were again persuaded that, for the long-term investor, stocks are the preferred low-risk investment. Indeed, stocks were seen as so very low risk that we tolerated a 1 percent yield on stocks, at a time when bond yields were 6 percent and even TIPS yields were north of 4 percent.
• From the peak in 2000 to year-end 2008, the equity investor lost nearly three-fourths of his or her wealth, relative to the investor in long Treasuries.

This is an in-depth analysis and worthy of a back to back read, from one of the industry's pre-eminent philosophers, as well as the innovator of FTSE-RAFI Fundamental Indexes.

The full report can be read and printed here.