Wafe Pfau, Associate Professor of Economics at the National Graduate Institute for Policy Studies in Tokyo, Japan, has published new research showing that, contrary to the incessant marketing campaigns of The Stock-Selling Industry, market timing always works. That is, those who change their stock allocations in response to big price shifts with the aim of keeping their risk profiles roughly constant obtain far higher returns while taking on greatly reduced risks than do those following widely promoted Buy-and-Hold strategies.
Pfau states: “On a risk- adjusted basis, market-timing strategies provide comparable returns as a 100 percent stocks buy- and-hold strategy but with substantially less risk. Meanwhile, market timing provides comparable risks and the same average asset allocation as a 50/50 fixed allocation strategy, but with much higher returns.”
Pfau kindly credits my nine years of work in this field (during which I have argued forcefully that honest posting on safe withdrawal rates and other critically important investment-related topics should be permitted at every investing board and blog on the internet), saying “I am also extremely grateful to Rob Bennett for motivating this topic and contributing his experience and encouragement.”
In a show of his generosity of spirit, he also pays tribute to the leaders of the Bogleheads Forum, who have banned honest discussion of safe withdrawal rates and other important investment-related topics at their site, saying: “Because market-timing strategies are specifically not part of John Bogle’s investment philosophy, the author wishes to thank without implicating users including Adrian Nenu, afan, alec, Alex Frakt, bob90245, cjking, crl848, dmcmahon, DP, grayfox, Les, lostcowboy, market timer, matt, Mel Lindauer, Norbert Schlenker, peter71, pkcrafter, Rodc, SP-diceman, tadamsmar, wearethefall, and yobria.” That sort of comment heals wounds and heaven knows we need wound-healing in the Retire Early and Indexing discussion-board communities today.
The only part that I take issue with is the suggestion (Wade does soften the claim with use of the word “specifically”) that Vanguard Founder John Bogle does not see the merit in long-term market timing. Bogle talks out of both sides of his mouth on this question in nearly every speech he gives. However, the reality remains that Bogle has many times made the case for long-term market timing in clear and compelling terms. I learned about the need to engage in long-term market timing from Bogle’s book and Bogle has said in an interview that he believes Valuation-Informed Indexing can be a good strategy (he did not quite endorse it). It is true, of course, that Bogle often fails to distinguish between short-term market timing (which never works) and long-term market timing (which always works), presumably largely because of the marketing benefits that follow from encouraging investors in their Get Rich Quick fantasies (in fairness to Bogle, I believe that there is a good bit of cognitive dissonance at work here as well).
Pfau explained his purpose in conducting the study in posts he put to the Bogleheads Forum. Stock-selling experts have been telling us for decades that “timing doesn’t work.” And, indeed, many studies have been produced showing that short-term timing (changing your stock allocation because of some expectation of how prices will move in the next year or two) does not work. But how about long-term timing (changing your stock allocation in response to big price shifts with an understanding that doing so may not pay off for as long as 10 years)? Amazingly, Pfau was able to find only one serious study looking at this critically important question. Much of Pfau’s study is aimed at pointing out the flaws in the FIsher and Statman study, which evidenced doubts on the part of the authors about the merits of long-term timing.
It is of course a logical impossibility that long-term timing would not work, given Yale Economics Professor Robert Shiller’s research showing that valuations affect long-term returns. If valuations affect long-term returns, returns should be higher and risks should be reduced at times of low valuations. How could going with a higher stock allocation at times when returns are high and risks are low than one goes with at times when returns are low and risks are high not produce good long-term results? In a rational world, the question Pfau focuses on in his new study would have been analyzed in great depth by many researchers many years ago.
The only explanation for why it has not been is that InvestoWorld is today not generally a rational world. Modern Portfolio Theory (which posits that investors are paid higher returns for taking on more risk, the opposite of what logic says must often be the case if valuations affect long-term returns) has influenced our thinking to such an extent that we do not even know to research the most important questions facing us. As World-Renowned Portfolio Strategist Bob Dylan pointed out in his Idiot Wind Theory (a popular counter to the excessively rationalistic Modern Portfolio Theory), “we’re idiots, babe, it’s a wonder we can even feed ourselves.”
This does indeed appear to be the case. At least that’s what the 140 years of historical data available today for our inspection reveal to the researcher willing to listen to its Forbidden Message.
Pfau charts the nominal wealth accumulation of $1 invested at the start of 1871. The Buy-and-Hold strategy examined is a 100 percent S&P 500 portfolio. The baseline market timing strategy chooses either 100 percent stocks or 100 percent Treasury bills at the start of each year, depending on whether the value of P/E10 is below or above it’s historical average at that time.
The Buy-and-Hold portfolio was worth $95,404 at the end of 139 years. The Valuation-Informed Indexing portfolio was worth $124,147.
Pfau writes: “For every risk measure considered, the market-timing strategies result in less risk and higher risk-adjusted returns than the 100 percent stocks Buy-and-Hold strategy. The highest standard deviation for portfolio returns from market timing is 13.93 percent, compared to 18.02 percent for buy-and-hold. The Sharpe ratios are also larger using two different definitions, showing that market timing provides higher returns on a risk-adjusted basis…. The maximum drawdown, which is the maximum percentage drop in wealth between high points and any subsequent low points in the historical period, is also significantly less for market timing. The maximum drawdown was only 24.16 percent, compared to 60.96 percent for buy-and-hold.”
Noting that the Valuation-Informed Indexing portfolio is able to generate the same returns as the Buy-and-Hold portfolio while being out of stocks half of the time and thus putting itself at what should be a huge disadvantage according to Modern Portfolio Theory, Pfau also compares the Valuation-Informed Indexing portfolio, which has an average stock allocation of 50 percent, with a 50 percent Buy-and-Hold portfolio. In this case, the risks of the two portfolios are roughly equal but the returns for the Valuation-Informed Indexing portfolio are dramatically superior. The Buy-and-Hold portfolio has an end-point (2010) value of $13,426. The Valuation-Informed Indexing portfolio has an end-point value of $94,866.
The study concludes: “Valuation-based market timing with PE10 has the potential to improve risk-adjusted returns for conservative long-term investors.”
Truly amazing stuff!
We’re idiots, babe. But I think it would be fair to say that those who read this study and spend some time thinking through the implications that follow from it are perhaps a bit less idiots than they were on the day before they took that promising step into the light. Thank you, Wade Pfau!
Please find some room for reporting on this fellow’s work on your front page, New York Times editors! By the close of business today if at all possible!


Set forth below is the text of a comment that I put today to a discussion thread at the Free Money Finance blog on the topic of the merits or lack thereof of market timing:
Thanks for your kind words and thanks for indeed adding some thoughts that those listening in here very much need to take into consideration, MBTN There’s no question (at least in my mind, but I believe that I probably speak for a lot of people re this one) that you are making an important point.
Stock prices can be affected by either rational/economic factors or by irrational/emotional factors. I think we are in agreement re that. And I think we are also in agreement in a belief that we can never know for certain which it is that is having the dominant effect. So we don’t know everything that we would like to know.
The question is — What do we do about this unfortunate reality? There is no neutral ground. We either report the nominal stock price as if it is real (which is what we have been doing during the Buy-and-Hold Era). Or we let people know that there is good reason (but not 100 percent compelling evidence) that the nominal price is heavily affected by emotional inputs. The key message that I want to get across is that THERE IS NO NEUTRAL GROUND. Both of the two possible choices (ignoring the emotional inputs that we believe are there or incorporating the emotional inputs into a price adjustment) carry risks.
Consider the situation in January 2000. The P/E10 valuation metric (the metric used by most of the people who are best informed about valuation questions) indicated that stocks were priced at three times fair value. Say that there is an individual who has a nominal portfolio value of $600,000. If we ignore valuations (which is what we did during the Buy-and-Hold Era), we send him a portfolio statement saying that he possesses $600,000 in stock wealth. If we incorporate a valuation adjustment into our reporting of his stock value, we send him a portfolio statement saying that he possesses $200,000 in stock wealth.
You are right when you say that we do not know with certainty that the true metaphysical value of his portfolio is $200,000. But I am right that we do not know with certainty that the true metaphysical value of his portfolio is $600,000. And getting the number wrong in either direction is going to have horrible consequences for the economy. If you tell someone that he possesses $600,000 in wealth when he really possesses only $200,000, he is going to spend money on houses and cars and vacations that he cannot afford to spend. Then a few years later he is going to regret having overspent for all those years and is going to pull back on his spending and cause an economic crisis. I believe strongly that the crisis we are living through today is the consequence of 30 years of promotion of Buy-and-Hold Investing.
I think that a lot of people experience unease with the thought of putting any number on that portfolio statement other than 600,000. In people’s minds, the $600,000 is a hard number while the $200,000 number is just sort of a guess. So people say “it’s okay to mention that there might be some overvaluation present, but you have to report the $600,000 number on the portfolio statement.” This is where I get off the Buy-and-Hold reservation.
I acknowledge that the $200,000 number is not 100 percent solid. If you asked informed people, some would say a better number is $250,000 and some would say a better number is $150,000. But I really don’t think that there is any reasonable person who would say that the best number is $600,000, that there was zero overvaluation present in the market in January 2000. In January 2000 we were reporting numbers that we all knew to be wildly wrong on millions of portfolio statements because we were not as a society willing to look at these difficult questions squarely and come up with REASONABLE AND BALANCED solutions to them.
My claim is not that there is a perfect way to do things and that the Buy-and-Holders won’t go along. My claim is that there is a better way than the Buy-and-Hold way and that the Buy-and-Holders are using a demand for absolute 100 percent perfection that they apply only to non-Buy-and-Hold approaches get in the way of consideration of approaches that are better than Buy-and-Hold but something short of perfect. Using $600,000 as the portfolio number was no more “right” than using $200,000 (my personal view is that it was far less right). So why did all of our portfolios use the $600,000 number? Why was there not even a DEBATE about this at the time?
The consequences of avoiding the debate are huge. I discussed above the retirement question. I have a retirement calculator that includes a valuation adjustment. If this debate were proceeding as it should, that calculator would be getting linked at thousands of web sites where people could check it out and DECIDE FOR THEMSElVES whether they want to use valuation-adjusted numbers in planning their retirements or not. The reality is that the calculator is linked at only a tiny number of sites. Not because it does not add something important to the debate. Because Buy-and-Holders feel that it makes them look bad for people to see how far off their numbers turn out to be if a valuation adjustment is employed.
When there is not even a debate about these questions, there is no brake on the car. People have a natural tendency to want to see stocks overvalued — overvaluation makes for bigger numbers on our portfolio statements and we all want to be prepared for retirement as soon as possible. All humans have an inclination for self-deception and the only thing that can rein this in is a voicing of the dangers. But for so long as we do not permit the debate (because it embarrasses Buy-and-Holders), there can be no voicing of the dangers! And the worse the problem goes, the greater the embarrassment becomes!
We left the market no way to correct prices except through a huge crash. We did that by cutting off the only way that overvaluation steam can be released outside of a crash — HONEST and REASONED DISCUSSION of the risks of overvaluation. I am proposing a sea change in how investing analysis is performed. I am NOT disputing the point you are making, MBTN. I see it as an important and legitimate point and I consider you a friend for being willing to go to the trouble to advance it here. The sea change that I am proposing is in asking/insisting that in future days the Buy-and-Holders extend that same hand of friendship to Valuation-Informed Indexers, that we all think of each other as friends engaged in a mutual effort to overcome our personal flaws and come to the best overall answers we can come to.
I am biased. I have been invested solely in super-safe asset classes for 14 years. That inevitably biases me against stocks. But the Buy-and-Holders are also inevitably biased in favor of stocks. If we want our boards and blogs to work, we need to acknowledge these biases and make an effort to work together to give ourselves and others the best possible discussions of the issues possible. When all of the people on one side of the table are not participating because it has been made clear to them that their comments will be dismissed as “rude” if they state their honest views, the discussions become misleading and dangerous and irresponsible. None of us really want that. So we all need to make a greater effort to try to put ourselves in the shoes of the other fellow and treat him as we would want to be treated if we held his viewpoint.
That’s my strongly held belief re all this, in any event. It is possible that I am wrong on the substance. I am certainly sincere in what I am saying (my record shows this beyond any reasonable doubt whatsoever). Again, I need to say that I am grateful to FMF for providing the forum for this discussion and I offer to do anything that it is in my power to do to see that it proceeds to a good place for every single person involved in it or affected by it.
Rob