FactSet said the margin is more than double the index’s 6.3% average since 1946, as first-quarter earnings season nears completion.
The report said if margins reverted to that long-term mean, the S&P 500 could lose about half its value; even if they hold, projected real 10-year returns are 1.8% annually.
Analysts expect margins to rise to 14.6% by the fourth quarter, but Research Affiliates founder Robert Arnott warned competition and political backlash could push profits lower.
Is the S&P 500's record high a mirage hiding widespread weakness among most stocks?
Can AI's productivity gains permanently defy the historical reversion of corporate profit margins?
With labor's income share at a historic low, what is the biggest non-financial risk to the stock market?
S&P 500 Posts Highest Net Profit Margin Since 2009 at 13.4% Amid AI-Driven Efficiency Gains
Overview
In Q1 2026, the S&P 500 achieved a record net profit margin of 13.4% and a strong 27.1% year-over-year earnings growth, driven largely by the Information Technology sector's 29.1% margin and the dominant 'Magnificent 7' tech giants, which contributed 71% of the earnings increase. Rapid AI adoption, reported by 25% of companies and led by tech and finance sectors, fueled efficiency gains and profitability. Despite geopolitical risks from the Iran conflict pushing oil prices above $120, the market showed resilience, supported by expectations of stable Federal Reserve policy. Elevated valuations and concentrated tech leadership highlight the need for diversified, quality-focused investment strategies amid ongoing economic uncertainties.