A record share of Bitcoin's mining power is now helping secure Rootstock, a Bitcoin sidechain that relies on merged mining. In the first quarter of 2026, 84.01% of Bitcoin's total hashrate contributed to Rootstock, according to the sidechain's own methodology. That's up from earlier periods and reflects a broader trend: 93.10% of observed mining-pool hashrate participated in merged mining during Q1.
Who's mining Rootstock
The biggest pools are leading the charge. Foundry USA contributed 36.62% of the merged-mining hashrate, followed by AntPool at 19.92%, F2Pool at 12.79%, ViaBTC at 11.79%, and SecPool at 4.98%. Rootstock's figures are based on seven-day averages from Blockchain.com and extrapolated from blocks that mined both Bitcoin and Rootstock simultaneously.
Why miners are piling in
The timing isn't great for Bitcoin miners' core business. CoinShares called Q4 2025 the toughest quarter since the April 2024 halving, and hashprice — the daily revenue per petahash — hovered around $29/PH/day in Q1 2026. Hashrate Index currently puts the figure at $35.78/PH/day, with network hashrate at 984.34 EH/s and Bitcoin around $77,300. The 3.125 BTC block subsidy still dominates miner revenue, but margins are thin.
Rootstock's pitch is straightforward: miners can earn additional fees denominated in BTC without buying new hardware or interrupting their Bitcoin operations. The sidechain uses merged mining, meaning pools securing Bitcoin also secure Rootstock's blocks at no extra energy cost. For miners watching hashprice slide, that extra revenue stream is increasingly hard to ignore.
What comes next
Rootstock hasn't released projections for Q2, but participation rates above 90% leave little room for further growth from existing pools. The question is whether smaller pools or solo miners will follow, and whether the extra fees prove meaningful enough to offset the persistent pressure on mining economics. With Bitcoin dominance at 60.1% and the market cap near $1.55 trillion, the sidechain experiment is no longer niche — it's become a standard part of how pools operate.
