bitcoin's biggest miners left for ai. the network got stronger anyway.

daily ai × crypto news in 5 minutes. no hype, just what matters.

evening. the companies that used to define bitcoin mining are ripping out machines to rent their power to ai, and bitcoin is harder to mine than it has been in seven months. that's the big one. also: ethereum hits pause on its next upgrade over a gas bug, banks start locking out ai agents, and visa's rumored fireblocks deal gets a "not true." (this morning's quick read, with openai's reported $1.25t round and a16z crypto becoming a16z frontier, is in today's news of the day.)

the giants are unplugging. listed bitcoin miners have been turning mining sites into ai data centers all year. by blocksbridge consulting's count, the public miners it tracks shed about 56 eh/s of realized hashrate in the first half of 2026, a 23% drop, while their directly reported ai and hpc revenue rose 52% in a quarter. it values the machines pushed out at roughly $1.5b, using an assumed $20 per terahash. and it's not a pause: once a site is rebuilt and its power is committed to ai customers, "that capacity isn't waiting for a better hashprice to switch back on." (blocksbridge, miner weekly)

the network didn't notice. you'd expect bitcoin's total computing power to sag. instead, its seven-day average hashrate climbed back above 1 zettahash per second (1,000 eh/s) this week, the highest since march 3. the difficulty adjustment confirms it: difficulty rose 5.92% on oct 16, and mempool.space currently projects another ~5.5% rise around oct 29 (blocksbridge's earlier estimate: 5.16%). two back-to-back jumps would add up to roughly 11%. "that's hardly the breathing room remaining miners might have expected from the ai migration," blocksbridge wrote. (miner weekly, mempool.space, cointelegraph)

so who's filling the gap? some of it is in plain sight. bitdeer, which is also chasing ai, kept building: its self-mining capacity hit 82.3 eh/s in september, up from 35 eh/s a year earlier, and its co-mining arm grew to 28.7 eh/s from 21.6 eh/s, about 9.5 eh/s added in one month. the quieter part is the used-machine market. a site can leave bitcoin while its machines don't: resellers like sazmining list pre-owned antminer s21 xp rigs for hosting in paraguay and texas. on the new-hardware side, core scientific booked a $41.9m loss when it canceled a deal for chips worth 15 eh/s to focus on ai colocation. blocksbridge is careful here: the listings don't show how much public-miner gear actually lands with smaller buyers. (miner weekly)

why it matters. for bitcoin, it's good news: security doesn't depend on any one group of companies, and when the biggest players leave, the network routes around them. for the miners that stayed, it's a squeeze: more competition means a lower hashprice, with bitcoin stuck near $81k. and for markets, the "miner" stocks that tanked in the ai debt scare (we covered that in #002) increasingly trade as ai landlords, not bitcoin bets. blocksbridge calls it a reversal of 2021: the giants that crowded small buyers out of the hardware market are now stepping aside. more: bitcoin · ai

ethereum pauses glamsterdam over a gas bug. developers called off the upgrade's oct 26 activation on the hoodi testnet, along with a planned gas-limit increase to 200 million, after security firm chainsecurity showed that two of its pricing changes (eip-8037 and eip-8038) can change how existing contracts behave when a call runs out of gas. some contracts count on a failed call leaving too little gas to do anything but revert; under the new rules, gas can be refunded, so a failure could get recorded permanently instead. in the other direction, creating a new storage slot could cost 110,020 gas instead of 22,100. chainsecurity found 13 real-world contracts potentially affected and is contacting them. no new date yet, and mainnet (once eyed for early december) has no confirmed date. (coindesk, chainsecurity, cointelegraph, ethereum foundation)

fireblocks says visa talk is "not true at present time." axios reported visa was in late-stage talks to buy the crypto custody and stablecoin infrastructure firm for around $2.5b. fireblocks denied it. fireblocks was last valued at $8b in january 2022. (the block)

hsbc puts a stablecoin in a payments app. redcoin (rchkd), its first hong kong dollar token, is rolling out in payme to more than 3.3 million users and 100,000+ merchants. (coindesk)

banks are locking ai agents out. morgan stanley, jpmorgan, bank of america and citi are restricting third-party ai agents after spotting them inside customer accounts, axios reports. morgan stanley has begun blocking them, though it says it hasn't seen "rogue ai agents"; most banks are moving toward read-only access. the crypto read: if agents are going to move money, they'll need rails built for it, which is exactly the pitch behind agent payments. (axios, reuters via investing.com, cnbc)

as of ~8:35 a.m. et, oct 23 (coingecko):

a calm day, with bitcoin in a range under $1,000 and oil the new worry ahead of the fed's oct 27–28 meeting. more by topic: markets

mempool.space: an open-source bitcoin explorer that shows live fees, the mempool, mining pools, hashrate and a running estimate of the next difficulty adjustment (it's where today's ~5.5% projection comes from). free on the web and free to self-host (agpl-3.0); paid enterprise plans for unmetered api access. for bitcoin holders timing a transaction, and for anyone tracking the miner story above. (enterprise) more picks in the gweiwire tools catalog.

the oct 29 difficulty adjustment. if the projected ~5% rise lands, mining gets about 11% harder in two weeks while bitcoin sits near $81k. watch whether hashprice pressure pushes more listed miners into ai, and whether hashrate keeps climbing anyway.

that's the wire. the giants left, the machines stayed. back tomorrow. — gweiwire

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