Open interest in derivatives for Bitcoin, Ethereum and Solana increased as crypto prices recovered, with Santiment recording a combined total of about $41.6 billion on Oct. 21, 2026. Bitcoin accounted for $23.4 billion, Ethereum $15.5 billion and Solana approximately $2.7 billion. Open interest measures the value of outstanding futures and perpetual contracts that have not been closed or settled, but does not show whether traders are positioned for gains or declines. Ethereum posted the clearest and most sustained increase since August. Bitcoin’s open interest was recovering but remained below its spring highs and an earlier September reading of about $25.84 billion. Solana showed greater volatility. Santiment said rising open interest alongside prices indicates stronger participation and increased appetite for leveraged positions, while warning that a reversal could trigger cascading liquidations. Traders are also watching funding rates, liquidation volumes and whether leverage grows faster than prices.