Table of Contents
Table of Contents

How War Affects the Modern Stock Market

A look at investor attitudes to war and uncertainty in the modern era

Russia has invaded its neighbor Ukraine, a conflict that may ultimately draw the U.S. and NATO into a larger war. There is also the ongoing possibility of an armed conflict between the U.S., its allies, and Iran and test launches by North Korea of ballistic missiles. As of 2022, the U.S. has spent an estimated $8 trillion on post-9/11 wars, a sizable piece of GDP.

But how do wars affect the economy and stock markets? Security experts are weighing in, and only time will tell, but investing experts are sending out reminders that past wars didn't push U.S. equities lower over the long term. How will markets react this time?

Key Takeaways

  • Though war and defense spending can amount to a sizable portion of the U.S. GDP, wars often have little sustained impact on stock markets or economic growth at home.
  • Markets largely have ignored recent conflicts related to the Middle East and Iran.
  • A war between Russia, Ukraine, and NATO allies, however, may have a more severe impact, especially on oil and other commodity prices.
  • Still, stock markets recovered to pre-invasion levels only a matter of weeks after the invasion of Ukraine by Russia.

Markets Often Shrug It Off

LPL Financial research notes that stocks have largely shrugged off past geopolitical conflicts. "As serious as this escalation is, previous experiences have indicated it may be unlikely to have a material impact on U.S. economic fundamentals or corporate profits," said former LPL Financial Chief Investment Strategist John Lynch, referring to the January 2020 U.S. airstrike that killed Iranian general Qasem Soleimani. "We would not be sellers of stocks into weakness related to this event, given stocks have weathered heightened geopolitical tensions in the past."

"From the start of World War II in 1939 until it ended in late 1945, the Dow was up a total of 50%, more than 7% per year. So, during two of the worst wars in modern history, the U.S. stock market was up a combined 115%," wrote Ben Carlson, director of institutional asset management at Ritholtz Wealth Management, in an article about counterintuitive market outcomes. "The relationship between geopolitical crises and market outcomes isn't as simple as it seems."

Source: LPL Financial
Source: LPL Financial.

Another example is after Russia invaded Ukraine on February 24, 2022, it rattled global markets. In the U.S., the S&P 500 index fell more than 7% in the days and weeks immediately following the incursion, as the U.S. and other nations stepped up severe economic sanctions on Russia and investors worried about the impact of commodity prices. But, a month later markets had rebounded and the S&P was trading at a level higher than before the invasion, even as the price of oil remained elevated above $100 a barrel.

S&P 500 Index Price From When Russia Invaded Ukraine to a Month Later

S&P 500 Index From Feb 24 - Mar 24, 2022
S&P 500 Index From Feb 24 - Mar 24, 2022.

When Markets Can Suffer

History tells us periods of uncertainty like we're seeing now are usually when stocks suffer the most. In 2015, researchers at the Swiss Finance Institute looked at U.S. military conflicts after World War II and found that in cases when there is a prewar phase, an increase in the war likelihood tends to decrease stock prices, but the ultimate outbreak of a war increases them. However, in cases when a war starts as a surprise, the outbreak of a war decreases stock prices. They called this phenomenon "the war puzzle" and said there is no clear explanation why stocks increase significantly when war breaks out after a prelude. 

Similarly, Mark Armbruster, president of Armbruster Capital Management, studied the period from 1926 through July 2013 and found that stock market volatility was actually lower during periods of war. "Intuitively, one would expect the uncertainty of the geopolitical environment to spill over into the stock market. However, that has not been the case, except during the Gulf War when volatility was roughly in line with the historical average," he said.

Source: Mark Armbruster/CFA Institute
Source: Mark Armbruster/CFA Institute.

In terms of the Iran conflict, however, investors have had a muted reaction to the headlines. "If 2019 taught us anything, it’s that you have to try as best as possible to keep to your process and not get caught up in the headlines," said Strategas Technical Director Todd Sohn to The Washington Post. "In a sad way, I wonder if we’ve become used to it. I wonder if the market has learned to discount these events."  

"Part of the reason for the calm may lie in the changing structure of global oil markets and how the U.S. economy has become less vulnerable to energy price swings," said J.P. Morgan Funds Chief Global Strategist David Kelly in a note. "Part of the reason may be purely psychological. Today’s investors have seen the stock market recover from both 9/11 and the Great Financial Crisis, arguably the greatest geopolitical and economic shocks of our time. This makes it easier for investors to shrug off other events."

A broader conflict with Russia can also cause volatile oil markets, as Russia is a key producer of crude oil and natural gas, with pipelines feeding many parts of Europe. If Russia were to shut off the spigot or suffer significant oil infrastructure damage, it could lead to higher energy prices. Interruptions to the ports around the Black and Baltic Seas could also create even bigger shipping headaches and lead to food inflation as grains and other staples remain stuck at sea.

Why Do Stock Markets Remain Resilient Through Wars?

In the U.S. context, stock markets have tended to shrug off initial downturns predicated by conflict. In some ways, wars can benefit economies not directly affected by the conflict by boosting industrial production to meet the military needs of those engaged in battle. The development of new technologies, some of which can be applied to the private sector, is also often spurred on by armed conflict.

Which Stocks Do Best During a War?

In general, defense stocks (companies that produce weapons and armaments) tend to fare the best during a wartime environment. Energy companies may also see a boost in conflicts that result in higher oil and commodity prices.

How Have Stocks Performed at the Onset of the World Wars?

World War I: Stocks fell around 30% at the outbreak of WWI and markets were closed for six months. When they reopened, the Dow rose more than 88% in 1915.

World War II: The stock market actually rose by 10% just after Hitler invaded Poland in 1939. After the Japanese attack on Pearl Harbor occurred, stocks fell 2.9% but regained those losses in less than a month. From 1939 until the end of the war in late 1945, the Dow saw increases of 50%,

The Bottom Line

"Over the last few years, markets have been conditioned not to overreact to political and geopolitical shocks for two reasons: first, the belief that there would be no significant subsequent intensification of the initial shock; and second, that central banks stood ready and able to repress financial volatility," said Mohamed A. El-Erian, chief economic adviser at Allianz, in a Bloomberg column.

But he warned that investors buying the dip should use a selective overall strategy. "This includes emphasizing up-in-quality trades that are anchored by robust balance sheets and high cash flow generation, resisting the strong temptation for large-scale shifts away from U.S. assets in favor of international investments and reducing exposure to inherently less-liquid market segments that have experienced beneficial spillovers from extraordinary central bank stimulus and the general reach for yield and returns," he said.

Article Sources
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  1. Brown University, Watson Institute for International and Public Affairs. "Estimate of U.S. Post 9/11 War Spending, in $ Billions FY2001- FY2022."

  2. Congressional Research Service. "U.S. Killing of Qasem Soleimani: Frequently Asked Questions," Page 1.

  3. LPL Research. "What Mideast Escalation Means for Markets."

  4. Fortune. "The Relationship Between Geopolitical Crises and Market Outcomes Isn’t Simple."

  5. Brune, Amelie, et. al. "The War Puzzle: Contradictory Effects of International Conflicts on Stock Markets." Swiss Finance Institute Research Paper, No. 11-21, 2011, pp. 1-21.

  6. CFA Institute, Enterprising Investor. "What Happens to the Market if America Goes to War?"

  7. The Washington Post. "The Finance 202: Wall Street Shrugging Off Iran Mayhem."

  8. Reuters. "How a Russian-Ukraine Conflict Might Hit Global Markets."

  9. Forbes. "Nasdaq nears a bear market, but here’s how stocks have historically been affected by war."

  10. Bloomberg Quint. "Muted Market Reaction to Iran Strike Overlooks Key Uncertainties."

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