At block height 953,151, the Bitcoin network continues to hum along at nearly 859 exahashes per second — roughly 859 quintillion SHA-256 computations every second. But beneath the surface of this astronomical number lies a distribution pattern that has been quietly consolidating for years: just three mining pools now account for more than half of all blocks produced.
According to real-time data from mempool.space covering the seven-day window ending near block 953,151, the mining pool landscape is dominated by a tight oligopoly at the top:
| Pool | Blocks (7d) | Share | Cumulative |
|---|---|---|---|
| Foundry USA | 216 | 24.2% | 24.2% |
| AntPool | 161 | 18.0% | 42.3% |
| F2Pool | 110 | 12.3% | 54.6% |
| ViaBTC | 88 | 9.9% | 64.5% |
| SpiderPool | 84 | 9.4% | 73.9% |
| MARA Pool | 55 | 6.2% | 80.0% |
| Luxor | 42 | 4.7% | 84.8% |
| SECPOOL | 39 | 4.4% | 89.1% |
| OCEAN | 29 | 3.3% | 92.4% |
| SBI Crypto | 16 | 1.8% | 94.2% |
Out of 892 total blocks mined during this period, the top 10 pools captured 840 blocks — a staggering 94.2%. The remaining 52 blocks were mined by a long tail of smaller operations and, increasingly rarely, solo miners whose lottery-ticket approach to block discovery has become statistically improbable at current difficulty levels.
The Foundry Era
Foundry USA’s 24.2% share extends a dominance that began in early 2021, when it overtook AntPool — historically the dominant pool throughout the 2016-2020 era — as the network’s largest mining entity. Foundry’s rise tracked the broader migration of Bitcoin mining hashrate to North America following China’s 2021 mining ban, which overnight removed an estimated 50% of global hashrate from the network.
The top-two combination of Foundry USA and AntPool now commands 42.2% of blocks — a figure that, while below the 51% threshold that triggers existential concern, represents enough concentrated power that a coordinated block withholding or reorg attack by just these two entities would be theoretically feasible over a short time window.
Historical Context: The Ghash.io Shadow
This is not the first time mining pool concentration has raised alarms. In June 2014, the Ghash.io pool briefly exceeded 51% of Bitcoin’s hashrate, triggering a crisis of confidence that led the pool’s operator to voluntarily cap its share and prompted the Bitcoin development community to seriously examine the risks of pooled mining.
The industry response was twofold: first, the emergence of alternative pool payout schemes (PPLNS, FPPS) that made it less attractive for miners to concentrate in a single pool; and second, the development of Stratum V2, a next-generation mining protocol that allows miners to construct their own block templates rather than accepting them from the pool operator — effectively neutralizing the ability of a dominant pool to censor transactions or execute covert reorgs.
However, Stratum V2 adoption remains limited. As of mid-2026, only a handful of pools — notably OCEAN (3.3% share) and Braiins (via Slush Pool’s successor infrastructure) — have deployed V2 endpoints, and miner uptake has been slow.
Hashprice Economics
At 859 EH/s and a difficulty of 138.96 trillion, the Bitcoin network generates approximately 450 BTC per day in block rewards (144 blocks × 3.125 BTC post-halving). With BTC trading near $68,000, this translates to:
| Metric | Value |
|---|---|
| Daily miner revenue | ~$30.6 million |
| Annualized miner revenue | ~$11.2 billion |
| Hashprice ($/TH/s/day) | ~$0.036 |
| Hashprice ($/PH/s/day) | ~$35.70 |
Hashprice — the revenue earned per unit of hashrate per day — has been under persistent compression since the April 2024 halving, which cut the block subsidy from 6.25 BTC to 3.125 BTC. At $0.036/TH/s/day, a modern S21-class miner (200 TH/s) earns approximately $7.20 per day before electricity costs. At $0.06/kWh, that same machine consumes roughly $13 per day in power — a substantial negative margin that only the most efficient operators can narrow through stranded energy sourcing or heat-recapture revenue.
Geographic Concentration and Censorship Resistance
Mining pool consolidation carries implications beyond the technical risks of 51% attacks. Pool operators serve as the de facto transaction gatekeepers for their hashpower: they choose which transactions to include in blocks and which to exclude. While most pools today follow a policy of economic rationality — including all fee-paying transactions — the concentration of block template construction in fewer hands creates a single point of policy failure.
The international distribution of the top pools provides some geographic diversification: Foundry USA is based in the United States, AntPool operates from China and Southeast Asia, and F2Pool has historically been China-based with growing international infrastructure. However, the pool operator’s jurisdiction, not the miner’s, determines which legal regimes apply to transaction inclusion decisions.
What to Watch
As the network approaches block 1,000,000 — an event likely to occur in early 2027 — the hashrate concentration trend bears continued monitoring. Three indicators will signal whether the ecosystem is successfully diversifying:
- New pool entry: The last significant new entrant to the top-10 was MARA Pool (formerly Marathon Digital’s internal pool), which opened to external miners in late 2023.
- Stratum V2 adoption: If the percentage of hashrate using V2 endpoints rises above 10%, it would represent a meaningful structural improvement in mining decentralization.
- Solo mining success rate: A solo miner successfully solving a block at 138T difficulty would be a powerful symbolic event — an assertion that the network’s permissionless nature remains intact.
For now, the data at block 953,151 tells a clear story: Bitcoin mining is a big business dominated by a small number of institutional operators. Whether that concentration represents a transient phase in the network’s maturation or a permanent structural feature is a question that the next 100,000 blocks will answer.
— Encryption Archive · AeonD.org