March 2026 proved to be one of the most volatile months for U.S. equities in recent years, with the S&P 500 falling roughly 5% overall. Yet amid the broad selloff, a small group of energy and materials companies delivered standout gains, led by LyondellBasell Industries, which surged 40.1% to become the top-performing stock in the index.
Oil refiners Marathon Petroleum and Valero Energy also posted strong advances of around 30% and 28%, respectively, as energy-related stocks dominated the leaderboard. Their performance stood in stark contrast to the wider market, where more than 80% of S&P 500 constituents declined during the month.
The rally was driven primarily by a sharp spike in oil prices following escalating geopolitical tensions in the Middle East. Disruptions to supply chains pushed crude prices significantly higher, boosting margins for refiners and petrochemical producers.
At the same time, defensive positioning by investors led to capital rotating away from growth stocks and into commodity-linked companies with direct exposure to rising energy prices.
Overall, March highlighted a clear divergence in markets: while the broader index struggled, energy-linked firms emerged as the primary beneficiaries of geopolitical instability and commodity-driven demand.