受全球不确定性影响，华尔街录得自3月以来最大月度跌幅

Multiple authoritative financial sources, including CNBC, Bloomberg, J.P. Morgan, and Reuters, consistently report that major Wall Street indices—such as the S&P 500 and Nasdaq—experienced their largest monthly declines since March. These reports come from credible, time-sensitive financial outlets that provide primary market data and direct comparisons with previous months. No cited source contradicts the claim; all relevant reports from late February and early March 2026 confirm a significant monthly drop and specifically frame it as the worst since March of the prior year. While some sources focus on individual sectors or companies, the overall narrative and quantitative evidence align strongly with the statement. Given the consistency across multiple high-authority sources and the absence of conflicting data, the claim that 'Wall Street experienced its largest monthly decline since March' is highly likely to be true.