Iran War Reverses International Stock Rally; U.S. Markets Show Relative Resilience

The Iran war has fundamentally altered the investment landscape that was developing in early 2026. Prior to the conflict, investors were rotating out of U.S. equities into international markets based on significant valuation differentials, with European and emerging market equities trading at meaningful discounts to their U.S. counterparts [5]. This rotation was expected to accelerate into what many analysts anticipated would be a “banner year” for international stocks.

However, the outbreak of hostilities on February 28, 2026, has completely reversed this trend. According to Morningstar research, U.S. stocks have demonstrated relative resilience, falling only 2.8% since the war began, while the Global Markets ex-US Index has declined 8.0%—nearly three times the U.S. performance [2]. This dramatic divergence suggests that capital is flowing toward perceived safer U.S. assets amid Middle East geopolitical uncertainty, despite the United States’ direct involvement in the conflict through its bombing campaign alongside Israel.

Recent market data reveals the scope of volatility across major U.S. indices [0]:

Notably, the S&P 500 experienced its best two-day performance since the bombing campaign began, gaining 1.3% in mid-March, which some analysts interpret as a potential stabilization signal [3]. However, the overall trend remains one of elevated volatility and uncertainty.

Sector performance on March 20, 2026 reveals clear differentiation [0]:

• Energy (-0.08%)
  : Relatively resilient, outperforming all other sectors
• Financial Services (-0.48%)
  : Moderate decline
• Technology (-2.03%)
  : Elevated volatility despite recent strong earnings
• Utilities (-7.36%)
  : Worst-performing sector, reflecting defensive positioning

The Energy sector’s relative outperformance aligns with the conflict’s impact on oil markets. The S&P 500 Energy Index has gained approximately 29% year-to-date, making it the strongest major sector by a significant margin [4]. This performance reflects the direct impact of Iranian oil facility disruptions on global supply expectations.

The conflict has driven oil prices to surge more than 50% over a two-week period—one of the sharpest two-week moves on record [6]. According to Morgan Stanley analysis, the key economic risk centers on the conflict’s duration: sustained higher oil prices can broaden into other costs, raise the probability of “higher rates for longer,” and weigh on overall economic activity [7].

UBS economist Paul Donovan notes that investors are largely “looking through” the energy shock, assuming oil prices will ease over time [6]. However, reports indicate damage to oil facilities could take months to restore [8], which raises the risk of prices “staying higher for longer” and potentially impacting Fed policy decisions.

The current market behavior demonstrates classic safe-haven dynamics, where investors paradoxically gravitate toward U.S. assets during a conflict involving direct U.S. military participation. This reflects several factors: the depth and liquidity of U.S. markets, the historical resilience of U.S. equities during geopolitical crises, and the perception that U.S. companies are better positioned to navigate supply chain disruptions through domestic production advantages.

Morningstar analyst Pappalardo notes that companies in the tech sector have reported strong earnings growth and robust 2026 guidance, causing investors to refocus on domestic opportunities [2]. However, this resilience faces potential headwinds from higher energy costs, as energy can account for up to 60% of data center operator expenses [9]. The intersection of AI infrastructure buildout and energy price inflation represents a critical variable for tech sector performance.

February’s employment data, collected before the war began, showed weaker-than-expected hiring figures plus an increased unemployment rate [2]. This pre-existing economic softness, combined with potential inflation pressures from energy price spikes, creates a complex backdrop for Federal Reserve policy decisions. The central bank must weigh geopolitical inflation risks against signs of labor market cooling.

Despite the reversal in performance, the valuation differential that attracted investors to international markets persists. European and emerging market equities continue trading at discounts to U.S. counterparts [5]. A sustained resolution of the conflict could reignite international investment flows, suggesting the current reversal may be temporary rather than a fundamental re-rating of relative valuations.

• Elevated market volatility, as evidenced by continued VIX elevation [0]
• Potential for further oil price spikes if conflict expands geographically
• Recession concerns given weaker pre-war economic data combined with geopolitical risk
• Sector rotation volatility as investors reassess positioning

• Prolonged conflict could lead to sustained higher oil prices, broader cost inflation, and “higher rates for longer” scenarios [7]
• Extended valuation differentials between U.S. and international markets may create eventual mean-reversion pressures
• Political uncertainty surrounding 2026 midterm elections may be influenced by energy price trajectory [7]
• Tech sector data center economics vulnerable to sustained energy cost inflation [9]

• Energy sector outperformance may continue as conflict-related supply concerns persist
• U.S. market resilience suggests potential for relative performance capture during uncertain periods
• Valuation opportunities in international markets may emerge if conflict de-escalates
• Potential for market stabilization if conflict enters a prolonged but contained phase

The current market environment requires heightened attention to conflict developments, particularly any escalation or de-escalation signals. Oil price trajectory remains the primary near-term catalyst, with the next 4-6 weeks representing a critical window for assessing whether the current energy shock proves transitory or sustained.

The Iran war has created a sharp divergence in equity market performance, with U.S. stocks significantly outperforming international markets since late February 2026. Key metrics indicate U.S. equities fell 2.8% versus an 8.0% decline for international markets, a nearly 3:1 performance differential. Energy sector stocks have emerged as clear outperformers, gaining approximately 29% year-to-date, driven by oil price surges exceeding 50% over two weeks. The conflict has reversed the international investment rotation that was building based on valuation differentials, returning capital flows toward U.S. safe-haven assets despite the United States’ direct military involvement. Market stabilization signals have emerged in recent sessions, though elevated volatility persists across major indices. The duration and scope of the conflict remain the primary determinants of whether current market dynamics represent a temporary rotation or a sustained structural shift in global equity allocation preferences.