Quantile time-frequency connectedness and networks across cryptocurrency markets

Abstract Cryptocurrencies have regained mainstream attention, with Bitcoinx′s recent rally renewing investor interest across the digital asset space. This study focuses on the connectedness and spillover effects among seven major digital assets to examine the asymmetric relationships conditional on market conditions and time horizons. To emphasize the significance of short- and long-term trading dynamics, we explore the state dependence of linkages during extreme upward and downward market movements. Our findings suggest a significant connectedness induced by Litecoin and Ethereum. Short-term fluctuations are the dominant drivers of crypto-market vulnerability across quantiles and frequencies. Pronounced upper-quantile connectedness emerges consistently across all markets. Interestingly, major currencies, such as Bitcoin, Ethereum, Ripple, and Dash, act as receivers during upside and median market conditions, whereas Ethereum and Litecoin exhibit transmission effects. Moreover, no connectedness is detected between Ethereum and Bitcoin at extreme quantiles. The findings highlight the need for careful monitoring and risk assessment of extreme events, demanding careful risk monitoring during periods of turmoil.