According to Adrian (@adriannewman21), China's official ban on ICOs in September 2017 led to a significant retracement in Bitcoin (BTC) prices, with BTC dropping by approximately 30-40%. This historical price movement highlights the substantial influence of regulatory actions in major markets such as China on cryptocurrency volatility and trading strategies. Traders should remain vigilant for regulatory news from large economies, as such events have proven to trigger sharp short-term market corrections and create both risk and opportunity in BTC and other digital assets (source: @adriannewman21).