U.S. stocks at their cheapest in nearly 18 months. Why earnings season holds the key on whether to buy. - MarketWatch
1. S&P 500's forward P/E ratio fell to 18.01, below 10-year average. 2. Tariff uncertainties may depress earnings forecasts for companies in S&P 500. 3. Major stock selloff indicates heightened market volatility and investor caution. 4. BofA estimates a potential 15% drop in S&P 500 operating income due to tariffs. 5. Upcoming earnings season may reveal significant impacts of tariffs on corporate guidance.