The FTSE 100 is down today, October 17, 2025, primarily due to renewed fears surrounding the US regional banking sector. The sharp decline in the index reflects a selloff in banking stocks triggered by unsettling news from two American regional banks—Zions Bancorporation reported a $50 million charge-off on risky commercial loans, and Western Alliance Bancorp disclosed legal action over a fraudulent borrower. These developments have raised investor concerns about potential wider credit risks, reminiscent of banking crises in 2023, impacting global equity markets with a flight to safety. Major UK banks including Barclays, Standard Chartered, NatWest, HSBC, and Lloyds suffered significant losses, with declines of around 2.5% to over 5%. The financial sector's weakness dragged the FTSE 100 down by 1.3% to a two-week low. Additionally, energy stocks were hit by falling oil prices amid global demand worries, while industrial shares also declined in line with broader European market trends. Despite these downturns, some companies like Pearson and Man Group saw gains due to optimistic sales and asset growth projections. The overall market sentiment is further clouded by geopolitical and economic uncertainties, including ongoing trade tensions and inflation concerns. Investors are reacting to a fragile global economy amplified by elevated interest rates and instability in credit markets, fueling today’s steep FTSE 100 drop.