Two of the biggest names in bitcoin mining just told investors they are done mining bitcoin. IREN and Core Scientific both said this week that they expect to wind down their mining operations by December 31, and from January they will be AI data center companies instead. This is not a side project or a slow pivot. Mining now brings in less than a tenth of the money at either company, while renting out power and floor space to AI customers brings in the rest. The machines that used to chase bitcoin blocks are being pulled out to make room for GPUs, and two companies that helped define the mining industry are walking away from it on purpose.
The numbers made the decision for them
Core Scientific was once one of the largest bitcoin miners in the world, and its third-quarter results show how little of that business is left. Mining brought in just $17.5 million of the company's $232.9 million in quarterly revenue, about 7.5 percent, while colocation services brought in $215.4 million. Self-mining revenue fell to $12.3 million from $57.4 million a year earlier, and the company had nearly half as many miners running at the end of September as it did at the end of 2025. Chief financial officer Jim Nygaard told investors on Thursday's earnings call that the company expects to complete the wind-down during the fourth quarter and enter 2027 as a pure-play, high-density colocation provider. The pivot started in 2024 with hosting deals for CoreWeave, and Core Scientific now counts CoreWeave and AMD as customers under agreements covering roughly 1.1 gigawatts of capacity. The company also took $266.5 million in mining asset impairments in the first quarter of this year, a sign of how fast the old equipment lost value once the strategy changed.
IREN's numbers tell the same story from the other side of the world. The Australian-founded company reported $200 million in AI cloud revenue for the quarter, up 182 percent from the previous quarter and nearly 88 percent of its $228 million in total revenue. Mining revenue fell 58 percent to $28 million over the same period. IREN signed a five-year, $9.7 billion cloud contract with Microsoft in November 2025 and has built up a $20.3 billion backlog of AI work, and it aims to have the switch substantially complete by December 31, with only limited mining continuing into 2027. The company pushed back its target for reaching $4 billion in annual AI revenue from late 2026 to January 2027, and it still needs to raise about $6 billion of the $15 billion in spending planned through the end of fiscal 2027. Even so, the direction is clear, and the mining rigs are not coming back.
The AI trade giveth and taketh away
There is a twist in the timing that the two companies will not enjoy. Their shares fell hard on Thursday, IREN by about 17 percent and Core Scientific by about 11 percent, as part of the same AI stock selloff that dragged bitcoin below $76,000. The fear driving that selloff is that the AI data center boom may be slowing, which is exactly the business these two companies are betting their futures on. TeraWulf, another miner turned AI host, reported this week that its bitcoin mining revenue fell 69 percent while its AI leasing income surged, and Riot Platforms signed a $28 billion lease with Anthropic and is selling its mined bitcoin to pay for the build. Across the industry, public miners wrote down about $1.1 billion in asset value in the first half of the year as they restructured toward AI. The whole sector is making the same bet at the same time, and Thursday showed what happens to that bet when Wall Street gets nervous about AI spending.
What it means for bitcoin
For bitcoin itself, the departures are less dramatic than they sound. Mining is spread across many operators around the world, and the network keeps running no matter which companies decide to stop. What changes is the shape of the industry around it, because the public miners were the ones with cheap power, big facilities, and access to capital markets. Those assets are now being pointed at AI, and the companies that remain pure miners will be smaller and more specialized. The irony is hard to miss. Bitcoin miners spent years arguing that their power contracts and data centers were valuable in their own right, and they were right. The value just turned out to be bigger for training AI models than for mining bitcoin, and the market is now pricing them on that basis. Anyone holding shares in a mining company should check what business they actually own today, because the name on the ticker may no longer describe the work being done.
Two giants of bitcoin mining are quitting by New Year, not because mining failed but because AI pays several times more for the same power and the same buildings. The network will be fine, and the miners that stay will keep mining. The bigger story is that the AI boom has now swallowed the industry that grew up around bitcoin, and the companies that made the switch first are the ones that will live or die on whether the AI buildout keeps going.
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Author: Dorian Fenwick
Silicon Valley Newsroom
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