Big US banks, including JP Morgan Chase, Wells Fargo, and Citigroup, have issued warnings about financial stress among lower-income consumers. Wells Fargo's CFO highlighted that net loan charge-offs increased by 7 basis points from the first quarter to 57 basis points of average loans, driven primarily by higher losses in the commercial real estate office portfolio. Additionally, Wells Fargo reported a 70% rise in credit card losses. JP Morgan and Wells Fargo declared $3.5 billion in customer debts that cannot be repaid. Despite Citigroup posting a rise in earnings due to cost-cutting measures, Wells Fargo experienced a 6% drop in stock value following a net interest income miss, and JP Morgan's results failed to impress investors, leading to a 1.2% decline in its stock. Economists warn that a credit crunch could result in a wave of mortgage defaults, potentially harming the broader economy.