In the fourth quarter of the year, the prices of both Bitcoin and Ether experienced a significant decline, falling by more than 22%. This notable downturn occurred as the anticipated 'Santa rally' in December, which often sees an uptick in market activity and optimism, failed to materialize as many investors had hoped. As a result, the cryptocurrency market faced increased pressure, leading to substantial losses for these leading digital assets during that period.
source: https://www.coindesk.com/markets/2025/12/31/bitcoin-ether-drop-more-than-22-in-q4-as-december-santa-rally-fizzles