The cryptocurrency market witnessed a robust V-shaped recovery in altcoins this December, spurred by a rare technical signal from Bitcoin and a $13.5 billion liquidity boost from the Federal Reserve. Bitcoin's monthly Bollinger Band width fell below 100, a historical indicator of potential significant price rebounds, contingent on Bitcoin reclaiming the $93,500 mark. Institutional activities also played a crucial role in the market's resurgence. Vanguard's initiation of ETF trading and Tether's issuance of $1 billion in new USDT contributed to the positive momentum, further supporting the altcoin rally.