Stocks face earnings test with S&P 500 on pace for worst performance in a shutdown since 1990
1. S&P 500 faced uncertainty due to government shutdown and tariff fears. 2. Upcoming bank earnings may provide insights into economic realities. 3. Analysts have raised Q3 EPS estimates for S&P 500 companies. 4. Market volatility expected as historical trends show October's instability. 5. S&P 500 is 3% below its record close despite recent drops.