US Stock Market Trends: Seasonal Patterns and Pharmaceutical Growth

The US stock market faces a complex outlook as the historical “Halloween effect” approaches. This seasonal pattern suggests that stocks tend to perform better between November and April than between May and October. Historically, the period following US midterm elections has seen significant gains, with the S&P 500 averaging an 11.1 percent increase from late October to late April in studied years between 1990 and 2022.

However, several risks could disrupt this trend, including geopolitical tensions, uncertainty regarding interest rate paths, energy prices, and corporate earnings.

In the pharmaceutical sector, major US companies are demonstrating strength. Eli Lilly reported Q3 revenue of 24.4 billion USD, a 39 percent increase, driven largely by GLP-1 products Mounjaro and Zepbound. The company subsequently raised its 2026 revenue forecast. Similarly, Gilead Sciences reported a Q3 earnings per share of 2.55 USD, exceeding expectations, supported by double-digit growth in its HIV business.