Foundry and AntPool back Stratum V2 working group as miner margins tighten
Seven pools joined the open-standard effort ahead of a May 15 difficulty estimate and $36–$38 hashprice pressure.
Seven major Bitcoin mining pools joined the Stratum V2 working group to develop an open standard for how pools communicate with individual miners. The coordination push lands as difficulty is projected to rise again in mid-May and hashprice sits near breakeven for parts of the fleet.
Key Takeaways
- AntPool, Block Inc, F2Pool, Foundry, MARA Foundation, SpiderPool and DMND joined the Stratum V2 working group.
- Foundry controls nearly 30% of global pool hashrate and AntPool about 17.7%, based on Hashrate Index figures cited in the announcement.
- The next Bitcoin difficulty adjustment is estimated for May 15, 2026 at 5:58 PM UTC, rising from 132.47 T to 135.64 T.
- CoinShares estimates up to 20% of miners are unprofitable, with hashprice at $36–$38 per PH/s/day near breakeven for some operators.
Foundry, AntPool and Five Other Pools Join the Stratum V2 Working Group
AntPool, Block Inc, F2Pool, Foundry, MARA Foundation, SpiderPool and DMND joined the Stratum V2 working group on May 9 to collaborate on an industry-wide open standard for pool-operator-to-miner communications.
The headline here is participation, not a finished rollout. With Foundry and AntPool described as the two largest pools by hashrate share, the working group now includes entities tied to a large slice of global pool hashrate. Hashrate Index figures cited alongside the announcement put Foundry at nearly 30% and AntPool at about 17.7%.
That concentration matters because standards only change market structure when big pipes adopt them. A working group with small pools can be a technical footnote. A working group with the two largest pools is at least a credible attempt to set the default.
Stratum V2, Block Templates, and the Pool–Miner Control Point
In pooled mining, individual miners typically work from block templates provided by the pool operator. That template is the candidate block a miner is effectively trying to solve, including transaction selection and parameters.
Stratum V2 is positioned as an open protocol for that pool–miner communication layer. The stated goal is to avoid control by any single pool operator while giving miners more flexibility in choosing block templates.
The announcement also framed the competitive angle in latency terms: “Bitcoin mining is competitive and fragmented by design. It is a race for efficiency where a millisecond can determine whether a miner wins a block or loses to a competitor,” Stratum V2 said.
For traders, the key nuance is what is not in the release. There was no deployment timeline, no commitment that any named pool will switch production traffic, and no quantified performance gain beyond the claim the standard could reduce the time it takes pools to successfully mine blocks.
Mining Economics Backdrop: May 15 Difficulty Estimate and Breakeven Hashprice
The coordination push is arriving into a margin squeeze. The next Bitcoin difficulty adjustment is estimated for May 15, 2026 at 5:58 PM UTC, increasing difficulty from 132.47 T to 135.64 T, per CoinWarz estimates cited in the announcement.
CoinShares estimates up to 20% of Bitcoin miners are unprofitable under current market and economic conditions. CoinShares also put hashprice at $36 to $38 per PH/s/day, described as near or at breakeven for some miners.
If difficulty rises into a flat hashprice tape, the second-order effect traders care about is balance-sheet behavior. Marginal operators tend to respond with cost cuts, fleet churn, or higher BTC sales to fund operations. That is not guaranteed by this announcement, but it is the backdrop that makes “efficiency” coordination more than marketing.
Adoption Signals Traders Can Track Before the Next Difficulty Print
The first checkpoint is the May 15 difficulty adjustment itself. The threshold that matters is the realized print versus the 132.47 T to 135.64 T estimate, and whether estimates get revised meaningfully ahead of the timestamp.
Hashprice is the other live wire. The real test is whether the $36 to $38 per PH/s/day band holds through the adjustment or deteriorates further after difficulty steps up.
On Stratum V2 specifically, traders need proof of rollout, not working-group membership. Any public commitments from Foundry, AntPool, F2Pool, or the other named pools on production timing, measurable latency targets, or what share of their hashrate will run the standard would move this from coordination headline to operational catalyst.
CoinShares-style updates to the “up to 20% unprofitable” estimate will also matter as difficulty and energy costs shift. That figure is a rough proxy for how much hashrate is operating on thin ice.
Standardization Is a Real Shift—But the Trade Depends on Rollout Proof
I treat this as a coordination signal with credible participants, not an immediate profitability catalyst. Foundry and AntPool being in the room is the part that changes the odds that Stratum V2 becomes a default, because standards follow distribution.
This looks more like a sentiment catalyst than a fundamental shift until there is rollout evidence. If difficulty prints higher and hashprice fails to recover, the setup starts to look structural rather than narrative-driven, and the practical impact is whether Stratum V2 adoption measurably changes miner efficiency and the supply pressure coming from the marginal cohort.
