Stablecoins serve as the fundamental infrastructure for Decentralised Finance (DeFi), acting as the primary bridge between fiat currencies and the digital asset ecosystem. While peg stability is well-documented, the structural role stablecoins play in transmitting systemic risk to the broader market remains under-explored. This study uses copula-based approaches to quantify the transmission of volatility and activity from stablecoin to cryptocurrency markets. We demonstrate in-sample causality across daily, weekly, and monthly horizons. Furthermore, we show that incorporating stablecoin factors significantly reduces Mean Squared Error in cryptocurrency forecasting. Specifically, we link stablecoin volume and upside volatility to broader market volatility, indicating its role as dry powder. Finally, we establish economic value by demonstrating reduced risk in a cryptocurrency volatility targeting model when stablecoin factors are employed.

翻译：稳定币是去中心化金融（DeFi）的基础设施，充当法定货币与数字资产生态系统之间的核心桥梁。尽管其锚定稳定性已得到充分论证，但稳定币在向更广泛市场传导系统性风险方面所起的结构性作用仍未充分探索。本研究采用Copula方法来量化从稳定币市场到加密货币市场的波动性与活跃度传导。我们验证了日度、周度与月度时间跨度上的样本内因果关系。进一步研究表明，引入稳定币因子可显著降低加密货币预测中的均方误差。具体而言，我们将稳定币交易量与上行波动性关联至更广泛的市场波动性，表明其作为"储备弹药"（dry powder）的功能。最后，通过论证在加密货币波动率目标模型中使用稳定币因子可降低风险，我们确立了其经济价值。