Mining Pools Controlling 75% of Bitcoin Hashrate Join Stratum V2 Working Group

Stratum V2 has gained backing from seven of the largest Bitcoin mining pools, putting nearly 75% of global hashrate behind the open protocol that shifts block construction to individual miners. Foundry, AntPool, F2Pool, SpiderPool, MARA Pool, Block Inc., and DMND are all now backing the standard.

Seven Pools Representing 75% of Hashrate Now Support Stratum V2

The numbers give the commitment immediate weight. Foundry alone controls 34.2% of global Bitcoin hashrate. AntPool adds 14.2%, F2Pool 11.3%, and SpiderPool 10.5%, with MARA Pool contributing 4.7%, according to Hashrate Index data. Together with Block Inc. and DMND, the seven pools backing the standard represent close to 75% of all Bitcoin hashrate.

The Stratum V2 working group announced the new members last week. The Stratum V2 protocol was first proposed by Braiins in 2020. The working group was co-founded by Braiins and Spiral in 2022, but adoption had remained limited until now. With Foundry and AntPool now on board, the protocol has the reach it lacked for its first four years.

Stratum V2 Moves Block Construction to Individual Miners

Under the current Stratum V1 standard, pool operators decide which transactions go into each new block. Individual miners contribute computing power but have no say in transaction selection. That concentration has been the most persistent structural concern about modern Bitcoin mining.

Stratum V2 changes that by allowing individual miners to construct their own block templates. The protocol does not reduce hashrate concentration. The same large pools still command the same share of computing power. What changes is who decides the contents of each block.

A single pool controlling more than 30% of hashrate is a concentration risk on its own. That same pool also choosing the transaction order for its share of blocks compounds the concern. Stratum V2 separates the two.

Stratum V2 Adoption Arrives as Up to 20% of Miners Operate at a Loss

The timing aligns with a difficult stretch for the mining industry. CoinShares estimates that up to 20% of miners are currently operating unprofitably. Hashprice, the revenue a miner earns per unit of computing power, sits at $38.57 per petahash per second per day, near breakeven for operators running mid-generation hardware.

Network difficulty is set to rise again on May 15, from 132.47T to 135.64T, according to CoinWarz. Total network hashrate now sits at 998 exahash per second, continuing its climb toward 1 zetahash.

The economic pressure gives Stratum V2 adoption additional context. Miners operating on thin margins have reason to support governance changes that strengthen Bitcoin’s decentralization credentials, since the network’s long-term value proposition depends in part on the credibility of its distributed structure.