What Happens to Stocks During Wars — 80 Years of Data

World War II is the extreme case — the most devastating conflict in human history, and paradoxically, a period of substantial stock market gains. After the attack on Pearl Harbor on December 7, 1941, the Dow Jones Industrial Average fell approximately 7% over two trading days. The broader market continued declining, bottoming in April 1942 at roughly 20% below pre-Pearl Harbor levels. Then something remarkable happened. From its 1942 bottom to Victory over Japan Day in August 1945, the market roughly doubled. The explanation has nothing to do with optimism about war. It's economics: wartime manufacturing created a boom in GDP, unemployment effectively vanished as millions entered the military and factories, government spending surged, and — crucially — consumer spending was suppressed by rationing, meaning corporate earnings had few places to go but into retained earnings and capacity expansion. The WWII case established a pattern that would repeat: markets drop sharply on the initial shock, then recover as the economic machinery of war stimulates production, spending, and employment.

The Korean and Vietnam Wars illustrate an important distinction: short, decisive conflicts produce cleaner market patterns, while prolonged wars get entangled with other economic forces. The Korean War (1950–53) was sharp and relatively quick in market terms. When North Korea invaded South Korea in June 1950, the S&P 500 dropped approximately 14% in three weeks — a rapid, fear-driven selloff. But the recovery was equally swift: within three months, the market was back to pre-war levels, and by the end of the conflict period, the S&P 500 was up roughly 40%. The economic logic was similar to WWII: military spending boosted industrial production and employment. Vietnam (1964–75) tells a messier story. The market initially rose during the early escalation phase (the Gulf of Tonkin Resolution in 1964), and the initial military commitment didn't cause significant market disruption. The drawdown was modest — about 5%. But as the war dragged on through the late 1960s and early 1970s, the market struggled. Not because of Vietnam specifically, but because the war coincided with rising inflation, the end of the gold standard (Nixon Shock, 1971), the 1973 oil embargo, and social upheaval. By the mid-1970s, it was impossible to separate Vietnam's market impact from these overlapping economic crises. This is the first major lesson about long wars: the longer a conflict lasts, the more it becomes entangled with other economic forces, making the 'war impact' nearly impossible to isolate.

September 11, 2001, broke the pattern in one critical way: there was no buildup phase. Every other conflict on this list featured weeks or months of escalating tension before military action. The attacks on 9/11 were a complete surprise — no uncertainty premium, just shock. The New York Stock Exchange closed for four consecutive trading days, the longest shutdown since 1933. When markets reopened on September 17, the Dow Jones fell 7.1% in a single day and continued falling, losing 14.3% in the first five trading days. In total, the S&P 500 dropped 11.6% from its pre-9/11 close. But context matters enormously here. The market was already deep in a bear market caused by the dot-com bust. The S&P 500 had already fallen over 25% from its March 2000 peak before the attacks. September 11 accelerated an existing decline — it didn't create one. The recovery from the 9/11 shock specifically (not the broader bear market) was remarkably fast. The S&P 500 returned to its September 10 closing level by early November 2001 — roughly two months. The Afghanistan invasion on October 7, 2001, barely registered as a market event because investors had already processed the shock and were focused on economic fundamentals.

If you could only study one historical example of how markets respond to military conflict, the Iraq invasion of 2003 would be the one. It's the cleanest modern example of the uncertainty premium at work. For months leading up to March 2003, the debate dominated headlines: would the U.S. invade Iraq? UN weapons inspections, diplomatic maneuvering, and troop buildups created a sustained period of uncertainty that weighed heavily on markets. The S&P 500 dropped approximately 12% between November 2002 and its March 2003 bottom. Then, on March 20, 2003, the invasion began. The uncertainty was over. Whatever came next — and plenty of it would be bad — the question of 'will they or won't they' was answered. Markets responded immediately. The S&P 500 rallied approximately 30% over the following 12 months. Oil, which had spiked to $37/barrel in the buildup, settled back to the $25–30 range within weeks. Defense contractors saw the beginning of a multi-year outperformance cycle as government defense spending surged. The Iraq case also illustrates a subtlety: the rally wasn't because the war was 'good for the economy.' It was because the removal of uncertainty allowed investors to price risk more accurately. Markets can handle bad news — it's the unknown they struggle with.

The Russian invasion of Ukraine on February 24, 2022, is the most recent large-scale military conflict and the closest analog to a modern, interconnected global economy responding to geopolitical shock. The initial market reaction was relatively contained: the S&P 500 fell approximately 5.3% in two days. But like 9/11, the war landed on a market already under stress — the Federal Reserve was beginning an aggressive rate-hiking cycle to combat post-COVID inflation, and the S&P 500 had already declined from its January 2022 highs. The war-specific market impact was sharpest in Europe, where energy dependence on Russian gas created a genuine economic crisis. European natural gas prices surged over 300% during 2022, and the eurozone narrowly avoided recession. U.S. markets, while affected, were more insulated due to domestic energy production. In the U.S., the sector story was clear. Energy stocks (tracked by XLE ETF) surged 58% in 2022 — the best-performing sector by a wide margin — as oil prices spiked to $130/barrel. Defense stocks also massively outperformed: Lockheed Martin (LMT) gained approximately 37%, RTX Corporation rose about 17%, and Northrop Grumman (NOC) climbed roughly 38% as NATO nations accelerated defense spending. Meanwhile, the broader S&P 500 fell 19.4% in 2022. The Russia-Ukraine case adds an important modern dimension: in an interconnected global economy, wars can trigger sustained inflation through energy prices and supply chain disruptions, extending market pain well beyond the initial shock. StockCram is not affiliated with, endorsed by, or sponsored by any brokerage mentioned on this page. Individual stock and ETF mentions are for educational context only.

The historical framework we've built across 80 years and seven conflicts provides context — but every conflict is unique. The current U.S.-Iran tensions have characteristics that differ meaningfully from past conflicts: the Strait of Hormuz carries roughly 20% of the world's oil supply through a narrow chokepoint, Iran has documented cyber warfare capabilities that can target financial infrastructure, the sanctions regime creates complex economic dynamics, U.S. energy production has changed dramatically since the shale revolution, and Iran's relationships with China and Russia create geopolitical dimensions that didn't exist during the Gulf War. These structural differences don't invalidate the historical patterns — markets still process uncertainty in broadly similar ways — but they do mean that a simple 'it'll follow the Gulf War playbook' assumption would be oversimplified. We explore these differences in depth in our companion posts: how wars affect oil prices and the Strait of Hormuz examines the energy supply dynamics, and why the US-Iran conflict is structurally different covers the full picture of how this conflict diverges from historical precedent. For additional context on how policy-driven market disruptions like tariff escalations create analogous uncertainty patterns, see our tariffs analysis. Historical data is educational context. Past performance does not indicate future results. Every investor's situation is unique.

This is one of the most searched questions about war and investing — and the answer is more nuanced than a simple yes or no. War is not 'good' for the stock market. The initial reaction to military conflict is almost always negative, with drawdowns ranging from 5% to 20% historically. But wars have often been followed by recoveries, driven by two forces: wartime government spending stimulates certain sectors (defense, energy, manufacturing), and the resolution of uncertainty allows markets to price risk more accurately.

Common questions about how military conflicts have historically affected the stock market.