Panic season
For normal people in the U.S., August is about relaxing at the beach. But for grizzled practitioners of systematic equity strategies, August is the cruelest month. Ever since the “quant liquidity event” of August 2007, we spend August compulsively checking our phones and having nightmares about screens full of glowing red numbers.[1]
Even if systematic equities aren’t your thing, you need to be mentally prepared for an epic financial disaster over the coming three months. Historically, the period from August to October is when most U.S. financial crises have occurred, such as the stock market crash of October 1929.
Here’s a list of terrible things that have happened in the past fifty years in U.S. financial markets in the calendar months of August, September, and October:
- October 1987, stock market crash
- October 1997, Asian financial crisis
- September 1998, LTCM collapse
- September 2008, Lehman collapse
And here’s a list of terrible things in the other nine months of the year:
- March 2020, COVID
See the pattern?
Let’s do some back-of-the-envelope math. If we include August 2007, that’s five disasters occurring in August-October over the past fifty years, and one occurring November-July. So over the next twelve months, my non-rigorous analysis says there’s a 12% chance of an epic disaster, with a 10% chance of it occurring between August 2025 and October 2025 and a 2% chance between November 2025 and July 2026.
This seasonal pattern in disasters is not a recent development. Since the founding of the United States, its financial crises have disproportionately occurred between August and October. America’s first bubble, the “Scriptomania” of July and early August of 1791, was a speculative frenzy surrounding securities issued by the Bank of the United States. America’s first bubble was followed swiftly by America’s first financial crisis, when prices collapsed in mid-August 1791, and then America’s first bailout, as the Treasury stepped in with open-market purchases on August 17, 1791, as discussed in Miller (2018). Long before we had the Greenspan put or the Bernanke put, we had the Hamilton put, although Hamilton only succeeded in delaying what later blossomed into the Panic of 1792.
Subsequent financial panics in the U.S. all tended to cluster in the period August to October, when harvest occurred and money needed to flow from the big East Coast cities and into the Western agricultural regions. These included the Panic of 1857 (August), the Panic of 1873 (September), and the Panic of 1907 (October). As described by Sprague (1910):
With few exceptions all our crises, panics, and periods of less severe monetary stringency, have occurred in the autumn, when the western banks, through the sale of the cereal crops, were in a position to withdraw large sums of money from the East.
The tendency of financial panics to occur around October in the Northern Hemisphere has been noted at least since Jevons (1884), who blamed “the autumnal pressure in the money market.” Analyzing British markets, he said:
since 1825 all the severest pressures have either commenced or culminated in the last quarter of the year … prima facie evidence of a dangerous tendency in these months worthy of the deliberate attention of commercial men.
Jevons wanted the Bank of England to combat this seasonal “dangerous tendency.” Similarly, the U.S. Federal Reserve System was created in 1914 partly to prevent the seasonal occurrence of bank panics and to “furnish an elastic currency,” as discussed by Miron (1986).
The U.S. economy is no longer dominated by agriculture. So why do we still observe financial crises around harvest time? I’d say it reflects one enduring legacy of our agricultural heritage: summer vacations. Hong and Yu (2009) show that for North America and Europe, equity liquidity and trading volume are lower in August and September as market participants go on vacation.
My theory is that since liquidity is lower in August and September, we have a greater likelihood of observing a “liquidity event” then because markets are less able to absorb large orders. Let’s take the quant bloodbath of August 2007. One explanation is that a large Wall Street firm, stung by losses in subprime, tried to unwind a systematic equity strategy. Because equity markets were illiquid due to the absence of vacationing traders, these trades had high price impact and generated large losses for other market participants, causing them to also delever in a self-fulfilling cycle of unwinding.
While the summer vacation hypothesis is not a great fit for the stock market crash of October 19, 1987, it makes sense for many other crises, such as the Asian financial crisis in 1997 which began in Thailand in July and then worsened and spread through October.
Is there anything we should do in response to these historical patterns? Sell in May and go away? I doubt it. The optimal response to seasonal variation in return distributions is a complicated topic involving the relative strength of the seasonal patterns in risk versus reward as well as the trading costs of seasonally varying leverage.
I think the best we can do is to structure our portfolios to withstand adverse events, no matter when they happen to arrive. While disasters are more likely during panic season, they can strike in any month.
Let me conclude by quoting Mark Twain, who was familiar with the concept of financial disaster since he managed to destroy both his own fortune and his wife’s through various unwise investments. Here’s his view of stock market seasonality:
October. This is one of the peculiarly dangerous months to speculate in stocks. The others are July, January, September, April, November, May, March, June, December, August, and February.
Endnotes
[1] August 2007, like Satan himself, goes by many names. Quant quake. Quant meltdown. Quant crisis. Quantocide. Quantocalypse. Quant bloodbath. Quant extinction event. Quant liquidity crunch. For more details, see Daniel (2009).
References
Daniel, Kent. “Anatomy of a Crisis.” CFA Institute Conference Proceedings Quarterly vol. 26, (January 01, 2009): 11-21.
Hong, Harrison, and Jialin Yu. "Gone fishin’: Seasonality in trading activity and asset prices." Journal of Financial Markets 12, no. 4 (2009): 672-702.
Jevons, William Stanley. Investigations in currency and finance. Macmillan and Company, 1884.
Miller, Scott Christopher. “Never Did I See So Universal a Frenzy: The Panic of 1791 and the Republicanization of Philadelphia.” Pennsylvania Magazine of History and Biography 142, no. 1 (2018): 7-48.
Miron, Jeffrey A. "Financial panics, the seasonality of the nominal interest rate, and the founding of the Fed." The American Economic Review 76, no. 1 (1986): 125-140.
Sprague, Oliver Mitchell Wentworth. History of crises under the national banking system. No. 5624. US Government Printing Office, 1910.
Legal Disclaimer
These materials provided herein may contain material, non-public information within the meaning of the United States Federal Securities Laws with respect to Acadian Asset Management LLC, Acadian Asset Management Inc. and/or their respective subsidiaries and affiliated entities. The recipient of these materials agrees that it will not use any confidential information that may be contained herein to execute or recommend transactions in securities. The recipient further acknowledges that it is aware that United States Federal and State securities laws prohibit any person or entity who has material, non-public information about a publicly-traded company from purchasing or selling securities of such company, or from communicating such information to any other person or entity under circumstances in which it is reasonably foreseeable that such person or entity is likely to sell or purchase such securities.
Acadian provides this material as a general overview of the firm, our processes and our investment capabilities. It has been provided for informational purposes only. It does not constitute or form part of any offer to issue or sell, or any solicitation of any offer to subscribe or to purchase, shares, units or other interests in investments that may be referred to herein and must not be construed as investment or financial product advice. Acadian has not considered any reader's financial situation, objective or needs in providing the relevant information.
The value of investments may fall as well as rise and you may not get back your original investment. Past performance is not necessarily a guide to future performance or returns. Acadian has taken all reasonable care to ensure that the information contained in this material is accurate at the time of its distribution, no representation or warranty, express or implied, is made as to the accuracy, reliability or completeness of such information.
This material contains privileged and confidential information and is intended only for the recipient/s. Any distribution, reproduction or other use of this presentation by recipients is strictly prohibited. If you are not the intended recipient and this presentation has been sent or passed on to you in error, please contact us immediately. Confidentiality and privilege are not lost by this presentation having been sent or passed on to you in error.
Acadian’s quantitative investment process is supported by extensive proprietary computer code. Acadian’s researchers, software developers, and IT teams follow a structured design, development, testing, change control, and review processes during the development of its systems and the implementation within our investment process. These controls and their effectiveness are subject to regular internal reviews, at least annual independent review by our SOC1 auditor. However, despite these extensive controls it is possible that errors may occur in coding and within the investment process, as is the case with any complex software or data-driven model, and no guarantee or warranty can be provided that any quantitative investment model is completely free of errors. Any such errors could have a negative impact on investment results. We have in place control systems and processes which are intended to identify in a timely manner any such errors which would have a material impact on the investment process.
Acadian Asset Management LLC has wholly owned affiliates located in London, Singapore, and Sydney. Pursuant to the terms of service level agreements with each affiliate, employees of Acadian Asset Management LLC may provide certain services on behalf of each affiliate and employees of each affiliate may provide certain administrative services, including marketing and client service, on behalf of Acadian Asset Management LLC.
Acadian Asset Management LLC is registered as an investment adviser with the U.S. Securities and Exchange Commission. Registration of an investment adviser does not imply any level of skill or training.
Acadian Asset Management (Singapore) Pte Ltd, (Registration Number: 199902125D) is licensed by the Monetary Authority of Singapore. It is also registered as an investment adviser with the U.S. Securities and Exchange Commission.
Acadian Asset Management (Australia) Limited (ABN 41 114 200 127) is the holder of Australian financial services license number 291872 ("AFSL"). It is also registered as an investment adviser with the U.S. Securities and Exchange Commission. Under the terms of its AFSL, Acadian Asset Management (Australia) Limited is limited to providing the financial services under its license to wholesale clients only. This marketing material is not to be provided to retail clients.
Acadian Asset Management (UK) Limited is authorized and regulated by the Financial Conduct Authority ('the FCA') and is a limited liability company incorporated in England and Wales with company number 05644066. Acadian Asset Management (UK) Limited will only make this material available to Professional Clients and Eligible Counterparties as defined by the FCA under the Markets in Financial Instruments Directive, or to Qualified Investors in Switzerland as defined in the Collective Investment Schemes Act, as applicable.