Bitcoin Mining Pools Controlling 75% of Hashrate Back Stratum V2 Open Standard

In what industry watchers are calling the biggest decentralization move in bitcoin mining in years, seven of the largest mining pools have aligned behind Stratum V2, an open-source protocol that shifts block construction decisions from pool operators back to individual miners. Foundry, AntPool, F2Pool, SpiderPool, MARA Pool, Block Inc., and DMND all joined the Stratum V2 working group last week, collectively representing nearly 75% of global bitcoin hashrate.

Market Context

The move comes at a precarious moment for bitcoin miners broadly. CoinShares estimates that up to 20% of miners are currently unprofitable as hashprice—the revenue a miner earns per unit of computing power—sits at $38.57 per petahash per second per day, hovering near breakeven for operators running mid-generation hardware. Network difficulty is set to rise again on May 15 from 132.47 terahashes (T) to 135.64T, according to CoinWarz data, while total network hashrate now stands at approximately 998 exahash per second.

Analysis

Stratum V2 represents a fundamental restructuring of how mining pools communicate with individual miners in those pools. Under the current Stratum V1 standard, pool operators control transaction selection for nearly every new block—deciding which transactions get included and in what order. That concentration has been the loudest structural concern about modern bitcoin mining for the past two years, particularly as a handful of pools have grown to command significant portions of network hashrate.

The practical change Stratum V2 introduces is allowing individual miners to construct their own block templates. This means the choice of which transactions get included sits with the actual miners doing the computational work rather than whoever operates the pool. While this does not reduce hashrate concentration—Foundry alone controls 34.2% of global hashrate—it fundamentally changes who makes decisions about transaction ordering and inclusion, which is the risk vector the Bitcoin community has flagged.

The protocol itself has existed since 2022, co-founded by Braiins and Spiral. Until now it had been treated as a niche side project with limited adoption beyond specialized operators. The working group framed Foundry and AntPool's involvement as marking the start of a new phase of accelerated deployment for the standard.

Key Numbers

- Foundry controls 34.2% of global bitcoin hashrate, making it the largest single pool by share

- AntPool commands 14.2% of hashrate, the second-largest signatory

- F2Pool represents 11.3% and SpiderPool 10.5% of network hashrate respectively

- MARA Pool contributes 4.7%, with Block Inc. and DMND rounding out the group

- Together, all seven signatories represent approximately 75% of total bitcoin mining hashrate

- Current hashprice: $38.57 per petahash per second per day

- Network difficulty scheduled to rise from 132.47T to 135.64T on May 15

What to Watch

Traders should monitor whether smaller mining pools follow the seven signatories in adopting Stratum V2, which would further cement the standard's position as the new norm for pool-miner communication. The timing of this announcement coincides with broader miner profitability pressures, and if hashprice continues declining or difficulty rises faster than expected, adoption momentum could either accelerate as operators seek efficiency gains or stall as stressed miners focus on survival over protocol upgrades. Watch whether Braiins and Spiral announce additional working group members in coming weeks and how the market responds to this structural shift in mining governance.

The implications for transaction ordering dynamics are significant. With 75% of hashrate now committed to a standard that returns template construction to individual miners, the days of pool operators unilaterally deciding which transactions get priority treatment may be numbered—though full deployment across participating pools will take time to implement.