Bitcoin mining has undergone a quiet but profound shift in power dynamics. The Stratum V2 working group announced that seven major pools — Foundry, AntPool, F2Pool, SpiderPool, MARA Pool, Block Inc., and DMND — have formally adopted the open-source protocol. These pools together control nearly 75% of Bitcoin's total hashrate, making this the largest decentralization move in mining in recent years.
According to Hashrate Index, Foundry alone accounts for 34.2% of the network's hashrate, followed by AntPool at 14.2%, F2Pool at 11.3%, SpiderPool at 10.5%, and MARA Pool at 4.7%. These five pools alone represent over 74% of the total.
75% Hashrate Backing Pushes Protocol From Niche to Mainstream
Originally launched in 2022 as a joint effort between Braiins and Spiral, Stratum V2 had remained a niche technical experiment for four years with limited adoption. The entry of Foundry and AntPool has reversed the situation dramatically. The working group described the collective endorsement as "the starting point for an accelerated deployment phase."
Stratum V2 Core: Block Template Autonomy Returns to Miners
Under the current Stratum V1 protocol, nearly every new block's transaction selection is controlled by pool operators, not the individual miners actually doing the work. This centralization has been a key structural concern for the Bitcoin community, especially when a single pool controls more than 30% of hashrate — transaction ordering power becomes a real risk.
Stratum V2 does not change hashrate distribution, but it changes who decides which transactions go into each block. Under the new protocol, individual miners can build their own block templates, reclaiming the right to include or exclude transactions from pool operators. This is precisely what the Bitcoin community has been pushing for.
Timing Coincides With Economic Pressure on Miners
The protocol shift arrives alongside severe economic strain on miners. CoinShares estimates that as many as 20% of miners are currently operating at a loss, with hashprice (revenue per unit of hashrate) lingering at $38.57 per PH/s per day — barely break-even for operations running older-generation machines.
Network difficulty continues to climb. CoinWarz data shows that on May 15, mining difficulty will rise from 132.47T to 135.64T, while total hashrate has reached 998 EH/s. That miners are choosing a protocol granting them more autonomy at a time of economic tightening is no coincidence.