Why I Don’t Invest in Momentum Stocks…Yet!

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Why I Don’t Invest in Momentum Stocks…Yet!

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(Last Updated On: January 18, 2017)

Confirmation bias is the tendency to cling to research/ideas that confirm with what you already believe. This behavioral bias leads to overconfidence and can impede our search for the truth. So in the spirit of healthy debate and ensuring we consider different perspectives, we asked Stig Brodersen, of The Investor’s Podcast, to post his thoughts on momentum, which is against every fiber of his value-investing body.

Here are Stig’s thoughts:

After reading the DIY Financial Advisor, one thought stuck with me. Should I start investing in momentum stocks? Now, this is actually a big intellectual leap for me. I’ve sworn to a value investing strategy for years, and really thought that this was the strategy I would use for the rest of my life. Therefore, I never really thought much about other strategies, but this time, it was different.

This wasn’t a new strategy that was written by a random person I didn’t know. The author was Wesley Gray – whose work I’ve long read – and I knew that he was a tried and true value guy with the same approach to investing as me. Recently, I even had the chance to interview Wesley’s co-author Jack Vogel specifically about momentum stocks, where he’s conducted a lot of research.

Our discussion evolved around the returns from the time period from July 1, 1963 through December 2014 (returns are gross of any fees and transaction costs):

  50% Value / 50% MOM 100% Value 100% MOM S&P500
CAGR 17.72% 15.69% 18.86% 10.23%
Std. Dev. 16.46% 17.48% 24.79% 14.86%
Sharpe Ratio 0.69 0.65 0.63 0.4

The results are hypothetical results and are NOT an indicator of future results and do NOT represent returns that any investor actually attained. Indexes are unmanaged, do not reflect management or trading fees, and one cannot invest directly in an index. Additional information regarding the construction of these results is available upon request.

So in a way, the results should speak for themselves and I should start jumping into momentum stocks, right? We’re looking at more than 8% outperformance compared to the overall market, and more than 3% compared to the value investing portfolio.

Well, it turned out that it wasn’t so easy. As an avid reader of the Alpha Architect’s articles and blogs, the concept of momentum stocks includes very frequent rebalancing. To derive the very best performance, we’re talking about monthly rebalancing. It also includes the DIY Financial advisor that refers to an academic paper suggesting 0.2% in monthly costs, which add up to a whopping 2.4% extra costs for the momentum strategy. That said, even with the extra costs, the momentum strategy still beat the value investing strategy, so I was still left explaining to myself as to why I couldn’t execute on a momentum strategy.

Beyond my internal intellectual struggle with momentum was the fact that I couldn’t find many good value bargains, and with my expectations of a portfolio of value stocks to deliver meager returns at best at the current price levels, I felt I was painting myself into a corner. Perhaps it could all be boiled down to irrational emotions? As many other investors, I constantly feel myself being manipulated by my own emotions to NOT do the right thing, but rather what my gut told me to do.

Regardless, I simply can’t come around to momentum investing and the reasons below describe why this is the case.

My reasons not to invest in Momentum Stocks

After my interview with Jack Vogel was posted, Wesley Gray reached out to me and asked if I was interested in writing a piece about my hesitation concerning momentum stocks. He thought that it would spike a great debate – a debate I would love to participate in. While I do consider myself a value investor, I’m also very aware that I’m on the path to life-long learning and I both hope and expect my current belief to be constantly challenged. So here is my 4 main reasons (feel free to read: “Excuses”) for not investing in momentum stocks.

1) I like my portfolio to be backed by undervalued companies

As we all know, the core of value investing is to have my stock pick’s intrinsic value vastly exceed the current market price based on both stable earnings and a strong balance sheet. In other words, when I look at my portfolio, I like to see companies where I pay very little for my cash flows, and a balance sheet with little or no debt and flooded with cash. Strong tangible and intangibles assets backing the valuation make the portfolio even more attractive.

I’ve found this approach to be profitable, and I find it just as important to see a correction or a crash and the strong fundamentals relieves me from the stress other investors often experience.  I see a $100 bill that might cost $80 getting even cheaper and I see a great opportunity to load up on even more value stocks.

But how would I feel when my portfolio of momentum stocks drop in price? Will I see a portfolio of very expensive stocks where the price and value simply converge? Isn’t that the effect that all value investors expect to occur, and the whole reason why value investing is profitable?

2) I don’t know the true costs of trading momentum stocks

It’s hard to find the true costs of trading momentum stocks. Well, to be completely honest, it’s basically impossible to find the true costs of any investment strategy. How much do we actually pay in commissions and spreads? These costs are dependent on so many factors, including trading skill, terms with your broker, liquidity, portfolio requirements, opportunity costs, and many other non-transparent factors. As previously mentioned, a momentum strategy should preferably be rebalanced monthly and we know that frequently rebalancing – no matter how you put it – is very costly.

DIY Financial Advisor points to the following research paper: “The Illusory Nature of Momentum Profits” for further investigation. The paper is highly critical about the momentum stock approach and abnormal returns the authors of the paper acknowledge exists. They directly state: “We conclude that the magnitude of the abnormal returns associated with these trading strategies creates an illusion of profit opportunity when, in fact, none exists.”

No one knows the future and while I think momentum stock will likely continue to outperform the market, as investors we must always remind ourselves that future returns are uncertain while costs are very certain.

3) James O’Shaughnessy got me thinking…

Recently I had the great honor to speak with legendary investor James O’Shaughnessy. I consider Jim to be a top authority on quantitative investing. I asked him about how different versions of his best-selling book, “What Works on Wall Street,” showed that different metrics interchangeably best outperformed the market. His response: “When you see a lot of academic research on an outperforming metric is conducted, expect to see that return diminish in the future.” You can find my full interview with James O’Shaughnessy here.

Now, this concern has obviously been raised before. We have always seen outperformance in the market for value metrics like a low P/E and P/B for instance, and the outperformance doesn’t seem to vanish even though the information is publicly available. The explanation for this is simple: Unless large pools of capital in equities markets, in aggregate, start to subscribe to a value investing method, the premium will continue to exist. We don’t expect that to happen anytime soon, because value investing is a strategy that is harder to sell to potential investors, and has long periods with underperformance.

My concern is not that all the big funds will start applying a momentum strategy. I simply don’t think they can find enough investors where the strategy appeals to them. However, I think that James O’Shaughnessy has a great point. While we didn’t talk specifically about momentum stocks, my concern is that too many small funds will start applying a price momentum strategy.

So how is this not as sustainable as value investing? The answer is that it might be. However, it seems to me that the overall premium is harder to erode simply because so many different value-investing metrics can be applied. You can easily find more than a dozen metrics including P/E, P/B, P/FCF, P/S, and EBIT/EV and while there is some overlap, it allows for many investable stocks that can outperform the markets.

A momentum strategy that is built around a previous price appreciation might simply be more vulnerable if my thesis is correct about fewer stocks being available when there is competition. To keep transaction costs low, a momentum strategy is forced only to focus on the biggest and most liquid companies – otherwise the spreads will simply dilute the returns too much.

A clear counter argument is that many more funds and individual investors follow a value approach, so why there is say, X times as many stocks available, X times as many people are buying the value stock up and the difference in performance is proportionally the same. That might be true, but in any case this adds an extra layer of uncertainty for me that I don’t feel I have with value investing.

4) I don’t expect a long bull market in the future

Yep… you heard me right. I’m putting on my tin foil hat and saying that the stock market is overvalued and it could crash. Whenever people come with predictions, I’m skeptical, and I hope you are too. That said, when I look at overall indicators like Schiller’s P/E, Tobin’s Q, and Total Market Cap to US GDP, I don’t like what I see. While the fourth and last reason as to why I don’t see myself investing in momentum stocks is by far my weakest argument, I’ve included it because I consider it especially interesting from a research stand point.

In the event of a bear market, it’s deemed most likely that value stocks do better than momentum whereas a momentum strategy typically does better in bull markets. DIY uses the boom and the bust of the Internet bubble from 1998-2001 to support the argument. Arguably, it’s a short period, but intuitively it makes sense to me, and I wouldn’t be surprised if a longer study made the preliminary conclusion more robust.

While I have no idea how equities perform in the short run, I’m not optimistic about a long period with a bull market starting anytime soon.

This would change my mind about momentum stocks

It might surprise you, but I think I could consistently follow a momentum strategy – at least in theory. To understand this surprising statement, I need to confess something embarrassing: I used to believe in the efficient market hypothesis. Yes, of all those poor business school students that we like to make fun of because they don’t knowany better… I was the worst! In my younger days, if you had told me that the planet was flat, I would have believed you just as much if you told me that the market didn’t price all securities correctly. It was not before I personally worked with stocks and studied the literature away from common text books that I realized markets aren’t always 100% efficient.

But why do I highlight my old belief in efficient markets? Well, I bring this up because as I gained more knowledge, I completely changed my paradigm towards stock investing. Perhaps, this is what I need to do with momentum stocks? Despite all of my concerns I’ll be the first to say that I find momentum stocks very appealing, and while I’m skeptic, I’m ready to be proven wrong.

Perhaps my discussion about value investing vs. momentum investing with Alpha Architect CIO Jack Vogel was the first step into changing my paradigm. Perhaps it will be your first step too?

About the Author: Stig Brodersenstig-brodersen

Stig holds a master’s degree in Finance, has studied Business Analysis at Harvard University, and he’s the co-founder of the The Investors Podcast educational site. During graduate school Stig co-founded a consultancy firm, providing clients with legal and financial advice relating to personal finance. Upon graduation Stig sold his shares in the firm to become a commodities trader in one of Europe’s leading energy trading companies. Now, Stig works as a college professor teaching a variety of courses including financial accounting, investment and economics. Stig also owns the investment company Stig Brodersen Holding.

Stig’s the author of The Warren Buffett Accounting Book, The 100 Page Summary of The Intelligent Investor, and The 100 Page Summary of Security Analysis.


  • The views and opinions expressed herein are those of the author and do not necessarily reflect the views of Alpha Architect, its affiliates or its employees. Our full disclosures are available here. Definitions of common statistics used in our analysis are available here (towards the bottom).
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About the Author:

After serving as a Captain in the United States Marine Corps, Dr. Gray earned a PhD, and worked as a finance professor at Drexel University. Dr. Gray’s interest in bridging the research gap between academia and industry led him to found Alpha Architect, an asset management that delivers affordable active exposures for tax-sensitive investors. Dr. Gray has published four books and a number of academic articles. Wes is a regular contributor to multiple industry outlets, to include the following: Wall Street Journal, Forbes, ETF.com, and the CFA Institute. Dr. Gray earned an MBA and a PhD in finance from the University of Chicago and graduated magna cum laude with a BS from The Wharton School of the University of Pennsylvania.