Bitcoin Mining Pools Explained: Who Controls the Hashrate

On July 9, 2026, a hobbyist pointed a Bitaxe, an open source ASIC miner that costs around $150 and draws less than 20 watts, at Bitcoin’s network for a single overnight session. Eight hours later the device had solved block 957,382 entirely on its own, claiming the full 3.1382 BTC reward (the 3.125 BTC subsidy plus roughly 0.0132 BTC in fees), worth close to $200,000 at the time, according to CoinDesk’s write-up of the win. Statistically, a device running at that hashrate should need somewhere in the range of sixteen thousand years to find a block on its own. It happened in eight hours instead.

Stories like that are exactly why mining pools exist, and also why almost nobody actually mines the way that hobbyist did. Pointing one machine at Bitcoin’s proof of work puzzle is a lottery with brutal odds; pooling hashrate with thousands of other miners turns that lottery into something closer to a salary. But the same tool that smooths out variance for individual miners has also concentrated an outsized amount of influence over which transactions make it into the blockchain into the hands of a small number of companies. This piece works through how pools actually pay out, who controls the most hashrate heading into the second half of 2026, why that concentration matters more for censorship than for the 51 percent attacks it usually gets blamed for, and why a protocol rewrite called Stratum V2 is trying to claw some of that power back.

How Bitcoin Mining Pools Actually Work

Bitcoin miners compete to be the first to find a number, a nonce, that makes a block’s hash fall below a target set by the network’s difficulty. After the difficulty adjustment on July 11, 2026, that target corresponded to a difficulty of roughly 127.17 trillion, with the network guessing at a combined rate of around 908 exahashes per second, according to CoinWarz’s difficulty tracker. A single Bitaxe-class device guesses at a small fraction of a single exahash, which is why the July 9 win above was headline news rather than a routine Tuesday.

Pooling solves the variance problem by combining hashrate from potentially hundreds of thousands of individual machines and splitting whatever reward the pool wins among everyone who contributed work. Miners do not submit fully solved blocks to a pool, they submit shares: hashes that clear a much easier, pool-set difficulty threshold and prove real work is happening, even though the overwhelming majority of shares are not good enough to win the actual block. The pool operator tallies shares, and whenever anyone in the pool finds a valid block, the reward gets distributed according to each miner’s proportional contribution. More than 95 percent of Bitcoin blocks today are found this way rather than by solo miners.

The idea is almost as old as Bitcoin mining itself. The first pool, Slush Pool, was launched in November 2010 by Marek Palatinus, known online as Slush, specifically to solve this exact variance problem for a community of hobbyist miners running consumer hardware. Slush Pool rebranded to Braiins Pool in 2022 and is still operating today, run by the same Czech company that later built the open source Braiins OS firmware and became an early champion of Stratum V2, a thread this piece picks back up later.

Payout Schemes: PPS, FPPS, PPS+ and PPLNS

How a pool converts shares into an actual Bitcoin payout is not a solved, one size fits all problem, and the scheme a pool uses says a lot about who absorbs the risk of bad luck. According to payout documentation published by Foundry USA and mirrored by most large pools, four schemes dominate the market.

Large, well capitalized farms that need predictable monthly cash flow to service debt or cover power contracts overwhelmingly prefer FPPS, even at a higher fee, because it turns Bitcoin mining into something closer to a fixed income stream regardless of whether their specific pool gets lucky in a given week. Smaller miners and the more ideologically driven corners of the mining community lean toward PPLNS or solo-style pools instead, accepting lumpier payouts in exchange for a lower fee and a scheme that cannot be gamed by opportunists who jump in only when a pool looks hot and jump out when it goes cold, the exact pool-hopping behavior PPLNS was designed to deter in the first place.

Who Controls Bitcoin’s Hashrate in 2026

Pool market share moves week to week as individual farms redirect hashrate chasing better fees or payout terms, so any snapshot is exactly that, a snapshot. Here is where things stood in mid-July 2026, according to Hashrate Index’s live pool tracker (Hashrate Index is published by Luxor Technology, which also operates its own pool, included in the table below).

Foundry USA has led the leaderboard for years, but its lead narrowed sharply in 2026. A CoinDesk snapshot from May 11 had Foundry at roughly 34 percent; by mid-July it had drifted down to around 26 percent while AntPool and F2Pool both grew several points. Add Foundry, AntPool and F2Pool together and either snapshot puts them at roughly 60 percent of the network combined, which means, per the Nakamoto coefficient tracked by mining research firm D-Central in its State of Bitcoin Mining H1 2026 report, just three pool operators control enough combined share to exceed half the network’s blocks. D-Central also put the market’s Herfindahl-Hirschman concentration index at roughly 1,492, which it describes as a lower-moderate concentration band: not dangerously centralized, but not exactly diffuse either.

One nuance worth holding onto: pools do not own the hashrate pointed at them. A pool operator is closer to a bank or a referee than an owner of mining equipment, and individual farms can and do redirect their machines to a different pool within minutes if fees or payouts turn unfavorable. That liquidity is a real check on any single pool’s power, but it does not eliminate the more specific risk pool concentration introduces, which has less to do with who owns the hardware and more to do with who gets to decide what goes inside a block.

The Real Risk Is Not a 51% Attack, It Is Transaction Selection

The most common fear attached to pool concentration is a 51 percent attack: a pool with a majority of hashrate could, in theory, rewrite recent transaction history or double spend coins. In practice, this scenario gets less scary the more you think through the incentives. Pulling it off against a network running roughly 900 exahashes per second would require controlling hundreds of exahashes of specialized, purpose-built hardware, worth many billions of dollars, on top of the electricity needed to run it continuously. That hardware would need the cooperation of a huge number of independent miners pointing hashrate at the attacking pool, any of whom could leave the moment they suspected foul play, and the attack itself would immediately crater confidence in the asset those miners are being paid in. Nobody has pulled it off against Bitcoin, and the economics argue strongly against anyone trying.

The more realistic risk is quieter. Under the mining protocol most of the network still runs, called Stratum V1, it is the pool operator, not the individual miner, who assembles a candidate block’s contents and decides which pending transactions to include. A miner’s ASIC is simply handed a template and told to search for a valid nonce; it never sees, let alone chooses, the transaction list inside that template. That means a pool controlling even a modest slice of hashrate has repeated, low-cost opportunities to quietly leave specific transactions out of every block it finds, without ever attempting the kind of dramatic, expensive rewrite a 51 percent attack implies.

F2Pool and the OFAC Censorship Question

That is not a hypothetical. In November 2023, pseudonymous developer 0xB10C, who runs a monitoring project called miningpool-observer, published research showing six transactions from addresses on the US Treasury’s OFAC sanctions list were missing from recent blocks. Two looked like accidents at ViaBTC and Foundry USA; four were traced to F2Pool and looked deliberate, according to CoinDesk’s reporting at the time.

F2Pool co-founder Chun Wang all but confirmed it in a since-deleted post on X: “Why do you feel surprised when I refuse to confirm transactions for those criminals, dictators and terrorists? I have every right not to confirm any transactions from Vladimir Putin and Xi Jinping, don’t I?” Under community pressure, Wang disabled the filter days later, but not before making a point that is more sympathetic to Bitcoin’s engineering culture than that quote suggests: he argued that a truly censorship-resistant system has to be designed to resist censorship at the protocol level, rather than relying on individual operators to simply behave. F2Pool, still one of the three largest pools at roughly 17 percent of hashrate today, has reportedly resumed similar filtering more than once since, most recently flagged by 0xB10C’s tooling in early 2025.

Marathon Digital, now MARA Holdings, tried the opposite experiment in 2021, launching an explicitly OFAC-compliant pool that only mined sanctions-screened transactions. It lasted less than a month before the company abandoned it amid backlash from the mining community. The market has, so far, rejected pre-compliant mining about as loudly as it rejected after-the-fact filtering, which is part of why the industry’s actual fix has focused on making selective filtering structurally harder rather than asking pool operators to simply behave better.

Stratum V2: Handing Block Building Back to Miners

Stratum V2 is a from-scratch rewrite of the communication protocol between miners and pools. It encrypts the miner-to-pool connection, which the older Stratum V1 sends in plaintext, and it is meaningfully more bandwidth efficient. The change that matters most for this piece, though, is a sub-protocol called Job Declaration. Under Job Declaration, a miner runs its own Bitcoin node, builds its own candidate block template from its own view of the mempool, and only hands the pool the resulting job, effectively telling the pool what it is working on rather than asking the pool what to work on. The pool still coordinates payouts and smooths variance across participants; it simply loses the unilateral ability to decide what a miner’s hashrate is trying to build.

The protocol picked up serious institutional momentum on May 11, 2026, when seven pools and mining companies representing close to three quarters of global hashrate announced they had joined the Stratum V2 working group, per the CoinDesk reporting cited above.

The Stratum Reference Implementation team behind the protocol has said it expects Stratum V2 to become the default on new ASIC firmware by the end of 2026. That is a milestone worth watching rather than taking for granted: pool-level endorsement is one thing, but Job Declaration only decentralizes anything once individual miners actually switch it on and start building their own templates. As of mid-2026, that miner-side deployment still lags well behind the pool-level commitments in the table above, which is the specific engineering bottleneck that determines whether Stratum V2’s decentralization promise becomes real or stays theoretical.

Job Declaration Goes Live

The gap between commitment and practice narrowed on June 25, 2026, when block 955,318 became, according to TFTC’s reporting, the first Bitcoin block mined in production with Job Declaration actually active: miner GoMining built its own block template and pool operator DMND, a Stratum V2-native pool that launched in November 2025, simply mined it. “A miner just mined the first Stratum V2 block to power their own product end to end,” DMND chief executive Alejandro De La Torre said. GoMining chief executive Mark Zalan framed the stakes more bluntly: “For years, mining pools have determined which transactions are included in Bitcoin blocks.”

One block does not undo years of pool-built templates, but it is the first concrete proof the architecture works outside a testnet. Every Job Declaration block that follows is one more block a pool operator could not have selectively filtered even if it wanted to, since it never built the template in the first place.

DATUM and Ocean: The Purist’s Path to Decentralization

Stratum V2 is not the only attempt to solve this problem, and it is not even the oldest. Ocean, a mining pool co-founded by longtime Bitcoin Core developer Luke Dashjr and mining engineer Bitcoin Mechanic, launched on November 28, 2023 with a $6.2 million seed round led by Block Inc chief executive Jack Dorsey. Ocean’s answer to pool centralization is a protocol called DATUM, short for Decentralized Alternative Templates for Universal Mining. Rather than waiting for new Stratum V2 firmware to reach the field, DATUM lets a miner run a full Bitcoin node plus a lightweight gateway that builds a block template locally, layered on top of the existing Stratum V1 infrastructure most hardware already speaks, with no firmware upgrade required.

That is the key practical difference from Job Declaration, which needs new firmware most existing ASICs do not yet run: DATUM works today, on hardware miners already own, at the cost of being a more bolted-on solution than a native protocol rewrite designed from the ground up for the same purpose. Both approaches are chasing the identical outcome by different routes, moving the decision of what goes into a block off a pool operator’s servers and onto equipment individual miners actually control.

Dashjr has been vocal about why this matters to him personally, framing template construction as exactly the kind of decision that should not be outsourced to a pool operator if Bitcoin wants to keep its long-term decentralization intact. In April 2026, after DATUM began producing blocks built by genuinely separate miners rather than a single pool’s template, he wrote on X: “OCEAN doing what it set out to accomplish. Instead of two blocks made by the same pool, we get blocks made by two independent miners, exactly the same as if they weren’t using any pool at all.”

Ocean remains small, around 2 percent of global hashrate as of mid-2026, but it has picked up an unusually credible backer for a pool that size: stablecoin issuer Tether began directing hashrate to Ocean in 2025, a vote of institutional confidence Dashjr called a strong signal that decentralization remains a core priority for Bitcoin’s future. Whether DATUM or Stratum V2’s Job Declaration ends up as the dominant path to miner-built blocks, or whether both simply coexist indefinitely, the fact that two structurally different fixes are both live in production today is the more important story.

The Pool Shakeout: SBI Crypto’s Exit and Industry Consolidation

Not every pool story in 2026 is about decentralization technology; some are simply about a brutal business getting more brutal. SBI Crypto, the mining arm of Japanese financial conglomerate SBI Group, announced it will permanently shut down its public mining pool on July 31, 2026, according to CoinDesk. The pool, which opened to the public in March 2021, still represents roughly 2 percent of global Bitcoin hashrate, all of which now has to find a new home before the cutoff (7:00am Japan time on July 31, or 10:00pm UTC on July 30). SBI has not given an official reason, though the closure follows a reported $21 million hack of company wallets in the fall of 2025 with suspected North Korean state involvement, and lands squarely inside an industry-wide margin squeeze this outlet has covered in detail. SBI has pointed departing miners toward Braiins, Luxor and NeoPool as alternatives, a small full-circle moment given Braiins Pool’s origin as the original Slush Pool discussed earlier in this piece.

SBI’s exit is a useful real-time illustration of a broader pattern. Thin margins push mid-sized and non-core pool operators to fold, and the hashrate they were running does not disappear, it redistributes toward whichever pools offer the best combination of fees, reliability and, increasingly, Stratum V2 readiness. That same consolidation pressure is squeezing individual mining companies into mergers and AI infrastructure pivots, a dynamic covered at length in our piece on the miner shakeout ahead of Halving Five.

Fees, Margins, and Why Miners Actually Switch Pools

Pool fees look small in isolation, a percentage point or two, but they compound into real money at industrial scale, and in a year where hashprice has spent long stretches near multi-year lows, every basis point matters more than it used to. Fee alone rarely decides the choice, though. Miners weigh several factors together:

• Payout scheme and how it matches their tolerance for variance (a small farm servicing debt wants FPPS certainty; a well capitalized operator chasing maximum long-run expected value may prefer PPLNS)
• Minimum payout thresholds and how frequently the pool actually pays out
• Server location and latency, since a slow connection to the pool’s stratum server increases the rate of stale, wasted shares
• Uptime history and whether the pool has ever had a payout dispute or security incident
• Whether the pool supports Stratum V2 and Job Declaration, an increasingly common checkbox for miners who care about the censorship question above
• Tax and accounting tooling, which matters more to smaller operators without in-house finance teams

Large, well capitalized farms overwhelmingly cluster around Foundry, AntPool and F2Pool for exactly these reasons: predictable FPPS payouts, deep liquidity, and infrastructure built for industrial scale. Smaller and more ideologically motivated miners are disproportionately represented at PPLNS-style and solo-friendly operations like Ocean, even though those pools will never challenge the leaderboard on raw hashrate.

Solo Mining and Rented Hashrate: Playing the Lottery on Purpose

Not everyone wants their variance smoothed out. A small but growing niche of miners deliberately skips pools altogether, using services like Public Pool, which the Bitaxe miner from the introduction used, that pay out the full block reward to the winner and effectively nothing to everyone else, functioning as something close to a lottery ticket with a razor thin house edge. Solo miners found 24 blocks in the twelve months leading into mid-2026, a 41 percent increase year over year, even as network difficulty kept climbing.

Rented hashrate has made that ticket even cheaper to buy. In February 2026, a solo miner turned roughly $75 of rented cloud hashrate into a full 3.125 BTC block reward worth about $200,000, mining block 938,092. Neither win was rational in an expected value sense, the odds of any single session succeeding remain vanishingly small, but cheap, accessible ASICs and rental markets have lowered the price of playing far enough that a small, steady stream of people keep buying in anyway.

Where Regulators Fit: The SEC’s Proof of Work Guidance

Mining pools sit at an unusually calm intersection of US securities law, at least for now. In a statement dated March 20, 2025, the SEC’s Division of Corporation Finance said that proof of work mining, whether solo or through a pool, does not implicate federal securities law, reasoning that rewards come from a miner’s own computational contribution rather than the entrepreneurial effort of a third party, the key test under the Howey framework, according to The Block. A year later, a broader interpretive release issued March 17, 2026 under chair Paul Atkins extended similar reasoning to staking, wrapping and no-consideration airdrops, part of the agency’s wider Project Crypto push. “This is what regulatory agencies are supposed to do: draw clear lines in clear terms,” Atkins said of the release. Readers who want the fuller mechanics of that legal test can find them in our explainer on the Howey test.

None of that guidance touches the censorship questions raised earlier in this piece, which fall under the Treasury Department’s OFAC sanctions program rather than SEC jurisdiction, or the hashrate futures and forward contracts some pools and miners use to hedge output, which sit with the CFTC instead. It is also worth noting for the Nasdaq-listed miners mentioned throughout this piece, MARA Holdings among them, that this SEC guidance is a staff-level statement rather than binding law; it shapes how public mining companies talk about risk in their own SEC filings, but it could in principle be revisited by a future commission. Mining pools have, so far, managed to avoid becoming a securities law fight even as almost every other corner of crypto has.

Pools vs Validators: Centralization Is Not Only a Bitcoin Problem

It is worth zooming out for a moment, because the pool concentration story is not unique to proof of work. Ethereum and other proof of stake networks route a similar amount of influence through a smaller set of actors: liquid staking protocols and large staking pools effectively decide which validators run, and by extension who gets to propose and build blocks, in a structure that rhymes with Foundry or AntPool’s role in Bitcoin. A single liquid staking protocol has at various points commanded close to a third of all staked ETH, prompting its own client-diversity campaigns and self-imposed caps aimed at avoiding exactly the kind of concentration this piece has spent so much time on. Our explainer on validator economics goes deeper on how stakers actually get paid and where that system’s own concentration debates stand today. The specifics differ, slashing risk instead of hashrate cost, delegated stake instead of physical machines, but the underlying tension is the same one running through this whole article: pooling is what makes participation accessible to ordinary users, and pooling is exactly what creates a small set of chokepoints worth watching closely.

What to Watch Before Halving Five

Bitcoin’s next halving is expected around April 2028, cutting the block subsidy from 3.125 BTC to 1.5625 BTC. That single fact reshapes almost everything discussed above. As the subsidy shrinks, transaction fees become a proportionally larger share of what pools and miners actually earn, which raises the stakes on exactly who controls block construction and fee-ordering logic even further. Our deep dive on the global hashrate migration underway ahead of Halving Five covers where the underlying compute is physically moving; this piece has focused on who coordinates it once it gets there. A few concrete things worth tracking between now and then:

• Whether Stratum V2 firmware actually reaches the Stratum Reference Implementation team’s end of 2026 default target, or slips
• Where SBI Crypto’s displaced roughly 2 percent of hashrate lands after July 31, and whether it further concentrates the top three pools or spreads out
• Whether Job Declaration blocks like June 25’s move from a single milestone to a routine occurrence
• Whether F2Pool’s OFAC filtering pattern resurfaces again, and whether wider Stratum V2 adoption makes that kind of filtering meaningfully harder to sustain

None of these are settled, and that is arguably the healthiest sign for Bitcoin mining right now: the fixes for pool centralization are not stuck in a whitepaper, they are shipping blocks on mainnet, even if slowly.

Frequently Asked Questions

What is a Bitcoin mining pool?

A Bitcoin mining pool is a coordinated group of miners who combine their hashrate and share block rewards in proportion to the work each miner contributes, measured in shares. Pooling turns Bitcoin mining from a rare, all-or-nothing lottery win into a smaller but far more predictable and frequent payout, which is why more than 95 percent of blocks today are found by pools rather than solo miners.

What is the difference between PPS and PPLNS payout schemes?

PPS, or Pay Per Share, pays miners a fixed, instant rate for every share submitted, with the pool operator absorbing all the risk of bad luck. PPLNS, or Pay Per Last N Shares, only pays miners when the pool actually finds a block, weighted by recent contribution, which shifts variance onto the miner in exchange for a lower fee. FPPS, a hybrid that adds average transaction fees to the PPS rate, has become the default choice for most large mining farms because of its predictability.

Which pool controls the most Bitcoin hashrate in 2026?

Foundry USA, a subsidiary of Digital Currency Group, has led the leaderboard for most of 2026 with roughly a quarter of global hashrate as of mid-July, though its share has narrowed from around 34 percent in May. AntPool, operated by Bitmain, and F2Pool, an independent pool founded in 2013, follow closely behind, together putting the top three pools at roughly 60 percent of the network.

Can a Bitcoin mining pool censor transactions?

Yes, at least under the older Stratum V1 protocol most of the network still runs. Because the pool operator, not the individual miner, builds a block’s transaction list, a pool can choose to exclude specific transactions, such as ones from sanctioned addresses. F2Pool was documented doing exactly this in 2023 and again in later years. Newer approaches, Stratum V2’s Job Declaration and Ocean’s DATUM protocol, both move block-building back to individual miners specifically to make that kind of filtering structurally harder.

What is Stratum V2 and why does it matter?

Stratum V2 is an encrypted rewrite of the protocol miners use to communicate with pools. Its most significant feature, Job Declaration, lets an individual miner build its own candidate block from its own node rather than accepting a template the pool built. Seven pools representing close to 75 percent of global hashrate joined a working group backing the protocol in May 2026, and the first block built this way in production was mined in June 2026, though widespread miner-level adoption is still in its early stages.

Written by the HOGE Wire research desk.