According to Stock Talk (@stocktalkweekly), the last major U.S. credit rating downgrade occurred in August 2023 when Fitch lowered the U.S. long-term credit rating from AAA to AA+. This downgrade led to increased volatility in both the traditional and cryptocurrency markets, with Bitcoin and Ethereum experiencing significant price swings as investors sought alternative assets amid concerns over U.S. fiscal stability. Traders responded by increasing positions in safe-haven digital assets and stablecoins, while monitoring macroeconomic indicators for further market-moving news (Source: Stock Talk Twitter, Fitch Ratings).