Public miners cut hashrate 13.4% for AI

Publicly traded Bitcoin miners cut their realized hashrate by 13.4% between the fourth quarter of 2025 and the second quarter of 2026, dropping from 368.3 exahashes per second to 319 EH/s. That's a faster contraction than the Bitcoin network as a whole, which slipped 10.6% over the same stretch, and it's happening because operators are moving power and data-center capacity toward AI and high-performance computing instead of mining.

The numbers behind the pullback

The decline reported by BlocksBridge Consulting in its Miner Weekly newsletter looks worse once you strip out Bitdeer, the one miner still scaling up. Excluding Bitdeer, the cohort's hashrate fell 21.2%, from 324.6 EH/s to 255.9 EH/s. Bitdeer itself grew 44%, to 63 EH/s, pulling the group average higher than it would otherwise be.

Revenue mix tells the same story from a different angle. Core Scientific booked $136.7 million in colocation revenue in the second quarter versus $27.5 million from mining. TeraWulf brought in $31.9 million from HPC leases against $12.8 million from mining. Both companies now earn most of their money from something other than Bitcoin. Riot Platforms and Bitdeer haven't made that switch yet; mining still accounts for the bulk of their revenue.

A cycle unwinding, not a mining exit

The framing matters here. This isn't miners abandoning Bitcoin, it's the post-China boom deflating. When China banned mining in 2021, operators relocated overseas and public companies raised capital to build out new sites in North America. That expansion cycle is now one halving past its peak, and the economics have flipped. Mining margins compressed while AI infrastructure demand exploded from 2022 onward, so the same power contracts and data-center shells that were built for hashing are getting repointed at GPUs.

That's a rational capital allocation decision, not a vote of no confidence in Bitcoin. A megawatt of grid power earns more from a hyperscaler colocation deal than from mining at current difficulty and block reward levels. Companies like Core Scientific and TeraWulf didn't sell their mining rigs, they just stopped prioritizing them when a better-paying tenant showed up. The split in the data is the tell: Bitdeer, which hasn't diversified, kept growing its hashrate because mining is still its whole business. Everyone else is behaving like a landlord who found a tenant willing to pay more per square foot.

The risk is concentration. If most public miner capacity keeps drifting toward AI leases, network hashrate growth increasingly depends on private miners, overseas operators, and companies like Bitdeer that haven't pivoted. That doesn't threaten network security on its own, but it does mean the public-miner cohort stops being a clean proxy for Bitcoin network health. Watching Core Scientific's stock price or TeraWulf's earnings call now tells you more about the AI data-center market than about hashprice or difficulty.

What would confirm the shift is permanent

Watch whether Riot Platforms and Bitdeer, the two holdouts still mostly mining, sign their own HPC or colocation deals in the next two quarters. If they do, it confirms the whole public-miner sector is repricing toward AI infrastructure and mining becomes a legacy line item rather than the core business.