Wall Street's main indexes opened lower on Thursday as investors avoided risky bets after another bout of tariff threats from President Donald Trump, while heavyweight retailer Walmart plunged on a downbeat fiscal 2026 sales forecast. Walmart slid 6.2% after the world's largest retailer forecast sales for the fiscal year ending January 2026 below estimates, as it anticipates inflation-weary consumers to pull back after several quarters of solid growth. "Walmart set a negative tone for expectations ... that's adding to concerns that the improvement in fourth quarter earnings were the result of weaker expectations for the first quarter of 2025," said Sam Stovall, chief investment strategist at CFRA.