Aggregate open interest in altcoin perpetual futures surpassed Bitcoin's for the first time since December 2024, with the shift reported on September 6 and during the week ending September 8, according to Coinalyze and market analysis. Bitcoin traded between $77,100 and $81,300 over 20 sessions and gained 1.4% from September 1 to 8, while the 29 largest liquid crypto pairs posted a median 10.2% gain. Zcash led the leverage expansion, with derivatives open interest near a record $2.4 billion and roughly $34 million in forced short closures during its decade-high rally. Bitcoin's advance was supported more by spot demand than altcoin leverage, but neutral funding, declining dominance and broader altcoin participation have increased risk appetite. Analysts cited a potential volume vacuum above $81,300 and warned that comparable leverage conditions preceded $1.7 billion in one-day liquidations, although the historical comparisons differ: December 2024 marked the prior open-interest crossover, while Michael Bucella separately compared the buildup with conditions before the October 2025 liquidation.