Definition. The total trading volume (in USD) of all futures contracts, including both expiry and perpetual contracts, where sellers were the aggressors, summed over a rolling 24-hour window.

Technical. Only trades quoted against USD-related currencies (fiat and stablecoins) on the native asset are included. The chosen data resolution (e.g. 10-minute, hourly) determines the cadence at which the trailing 24-hour sum is reported.

Interpretation. Surfaces aggregate sell-side flow across all futures over the trailing 24 hours, reading as a measure of selling pressure and recent market sentiment.