["Journal of Futures Markets, Volume 46, Issue 5, Page 904-930, May 2026. ", "\nABSTRACT\nDistinctive periodic patterns in trading activity at subsecond frequencies are present in the spot market and perpetual futures for Bitcoin and Ethereum at the major cryptocurrency exchange. Trading periodicity in the spot market is indicative of agency algorithms taking liquidity. The periodic pattern of trading activity in perpetual futures is symbolic of proprietary algorithms taking liquidity. Periodic surges in trading activity recurring at regular time intervals increase volatility and raise transaction costs, but they do not cause a significant adverse price impact. The largest share of price discovery occurs during the periods of trading activity associated with proprietary algorithms taking liquidity.\n"]