Should You Sell Investments During Times of Military Conflict?

When headlines turn to troop movements and missile strikes, investors often reach for the sell button. The immediate reaction is as old as the republic itself: uncertainty rises, markets wobble.

But history suggests a more nuanced story. While military conflict frequently delivers a short-term jolt to the stock market, the long-term trajectory has often proved more resilient — and, at times, rewarding for patient buyers.

The Shock Effect

Markets dislike uncertainty more than almost anything else. The outbreak of war introduces a variety of unknowns: duration, cost, geopolitical spillover and economic fallout.

When Germany invaded Poland in 1939, triggering the European phase of what would become World War II, U.S. markets initially fell as investors grappled with the prospect of another global conflict. Even so, the market decline was brief after the attack on Pearl Harbor formally pulled America into the war in December 1941. Within months, stocks began climbing as wartime production ramped up, and economic mobilization took hold.

A similar pattern emerged decades later. Following the Iraqi invasion of Kuwait in 1990 and the launch of Operation Desert Storm in early 1991, the S&P 500 dipped amid fears of oil shocks and prolonged instability. But once the campaign’s swift conclusion became clear, markets rebounded sharply, gaining more than 20% in 1991.

The lesson: markets often sell first and ask questions later.

Rallying Through War

The long arc of history shows that U.S. equities have frequently advanced during extended conflicts.

During World War II, the American industrial base surged. Defense contracts boosted manufacturing, employment and corporate profits. Between 1942 and 1945, the Dow Jones Industrial Average rose substantially, even as fighting raged overseas.

In the first few months after the September 11 attacks in 2001, which led to the U.S. invasion of Afghanistan, markets fell sharply as trading resumed. The broader campaign known as the War on Terror introduced prolonged geopolitical uncertainty. Yet over the following years, the market’s performance was influenced more by monetary policy, corporate earnings and, eventually, the housing bubble than by combat operations themselves.

Even the 2003 invasion of Iraq saw a familiar pattern. Leading up to the first strikes, volatility climbed. Once the conflict commenced and uncertainty diminished, stocks rallied in the months that followed.

Why the Pattern Repeats

To explain this repeating pattern, economists point to several forces at work.

• Markets are forward-looking. Prices tend to reflect anticipated risks before a conflict begins. When the “worst-case scenario” fails to materialize, relief rallies often follow.
• Government spending typically increases during wartime. Defense, logistics and technology sectors can see surges in contracts, stimulating segments of the economy.
• Historically, the Federal Reserve has provided liquidity during crises, cushioning financial shocks.

That doesn’t mean that war comes without economic costs. Inflation pressures, supply disruptions and rising national debt can weigh on long-term fiscal health. Moreover, some conflicts — particularly those with unclear objectives or prolonged instability — can sap consumer and business confidence.

Is a War-Driven Selloff a Buying Opportunity?

History suggests that sharp, fear-driven downturns tied directly to military action have often proved temporary. This pattern held for investors who bought during periods of peak uncertainty, including after Pearl Harbor, during the opening days of Desert Storm, and in the early phases of Middle East conflicts. Over the long term, they were generally rewarded.

But timing really does matter.

Not all downturns during wartime are caused solely by military action. The 1970s, for example, saw market struggles influenced by inflation, oil embargoes and structural economic shifts in addition to the Vietnam War. In those cases, broader economic forces played a larger role than battlefield events.

The consistent takeaway is that while markets may react sharply to the outbreak of hostilities, they tend to recover once uncertainty subsides and economic fundamentals reassert themselves.

For long-term investors, history offers cautious optimism. War may shake Wall Street in the moment, but it has rarely altered the enduring upward trajectory of American enterprise.

As sobering as global conflict may be, the stock market’s record suggests that panic has often been a poorer guide than patience.