Do clean and dirty cryptocurrency markets herd differently?

In this paper, we investigate the herding behaviour of two types of cryptocurrencies, referred to as "black/dirty" and "green/clean" based on their energy usage levels. Empirical results reveal that herding generally exists only in the dirty cryptocurrency market, and is more significant in down markets. Moreover, we find that clean cryptocurrencies do herd, but with dirty cryptocurrencies, when the two markets are both positive. Our findings are robust across value and equal-weighted portfolios and provide valuable insights to investors and policy makers.