September is crypto’s “bloodiest” month, historically marked by price drops and volatility for assets like Bitcoin ( $BTC ) and Ethereum ( $ETH ). Dubbed the “September Effect,” BTC has averaged -3.77% to -5.9% returns, declining in 8 of the last 12 years, with notable exceptions in 2015, 2016, and 2023.
This mirrors the stock market’s weak September performance, driven by post-summer sell-offs, portfolio rebalancing, and seasonal expenses. In crypto, profit-taking after summer rallies, high leverage liquidations, and macroeconomic uncertainties—like Federal Reserve meetings or global crises—amplify downturns. Low liquidity and trader psychology, fueled by awareness of the trend, create a self-fulfilling prophecy.
However, September often marks a “local bottom,” with October (+21%) and November (+46.81%) historically rebounding strongly. In 2025, post-halving dynamics and institutional inflows (e.g., ETFs, MicroStrategy’s BTC buys) may soften the dip, but volatility persists. Savvy investors see it as a buying opportunity before Q4 gains.
