According to Yahoo Finance's analysis of nearly a century of historical data, if the November 3 midterm elections result in a split Congress under President Donald Trump (with Democrats controlling one or both houses), the S&P 500 could see an average annual return of 7.33%. This is notably lower than the 14.52% average annual return observed when a Republican president oversaw a unified government. While a divided Congress could make passing major legislation and debt-ceiling negotiations more challenging, history also indicates that the stock market generally delivers positive returns regardless of congressional makeup.