What happened
On 30 October 2025 Riot Platforms reported third-quarter results including the figure it calls cost to mine, the cost of producing one bitcoin. Excluding depreciation of mining hardware it was **35,376 in the same quarter of 2024. Including that depreciation it was **75,505 (8-K exhibit).
The filing names the cause of the rise: "a 52% increase in the average global network hash rate as compared to the same period in 2024". The day before, difficulty had set a record of 155.97 trillion at height 921,312.
What it changes
It puts arithmetic where the argument usually is.
Revenue per unit of hashrate is (subsidy plus fees) divided by total network hashrate. Every term on the right is outside any individual miner's control.
The subsidy halved at block 840,000 in April 2024. Transaction fees were the hoped-for offset and did not arrive: fees were 9.9 percent of total block reward across 2023, 6.6 percent across 2024 and 1.1 percent so far in 2025 (chain data). And hashrate kept climbing, from a monthly average of about 624 EH/s in April 2024 to about 1,086 EH/s this month.
So a miner has exactly two levers, and both are on its own side of the meter. One is the price of electricity: MARA reported a direct energy cost of $0.039 per kWh at its owned sites for 2024 (8-K exhibit). The other is machine efficiency, which has gone from 34 J/TH for the S19 of 2020 to 12 J/TH for the S21 XP Hyd, per Bitmain's own specifications. A 2.8-fold efficiency gain, against a halved subsidy and a network that grew 74 percent. Riot's own numbers are what that subtraction looks like.
What it does not change
Nothing about the protocol. The difficulty adjustment does not consult anyone's margin. If enough machines switch off, the target falls and the survivors earn more per unit of work, which is the mechanism doing precisely what it was designed to do.
Cost to mine is also not a floor under anything. It is a company's cost of production, and production continuing has never required the producer to be profitable.
And the three figures in circulation are not the same figure. MARA's 46,324 is a cash cost excluding depreciation. The $89,074 includes the machines. Only the last one asks whether the hardware purchase was ever recovered, and it is the one least often quoted. Riot puts it at 77.9 percent of the production value of a bitcoin this quarter. A year ago the same measure was 123.5 percent.
Context
The pressure has been visible in what miners do with their sites rather than their machines. Core Scientific, which emerged from Chapter 11 in January 2024, contracted roughly 500 MW of critical IT load to CoreWeave for high-performance computing through that year, and today its shareholders rejected CoreWeave's all-stock offer for the company by 203.5 million votes to 20.8 million, and the merger agreement was terminated.
TeraWulf, Cipher and Applied Digital have signed away 200, 168 and 250 MW of critical IT load respectively on similar terms. What is being sold in each case is the interconnection, not the hashrate.