Bitcoin briefly dipped below $83,000 on Monday, impacted by thin liquidity and macroeconomic concerns from Japan. The decline was exacerbated by fears over a potential change in MSCI index methodology, which could exclude crypto-heavy firms from global indices, affecting over $137 billion in digital assets. Major altcoins, including XRP, ETH, ADA, and SOL, also experienced losses of up to 2%. Market analysts highlighted the fragile market structure and shallow order books as contributing factors to the downturn. A continued decline below $80,500 could see Bitcoin testing the $64,000 technical level, raising concerns among traders and investors.