Bitcoin Miners Drop 12% as AI Data Center Debt Reprices

Bitcoin miners that now sell AI and high-performance computing capacity took the worst of Wall Street's sharpest selloff since July. TeraWulf fell 12.64% on Wednesday, Core Scientific 12.44%, Cipher Mining 12.35% and IREN 12.2%, with Riot Platforms, Bitdeer, MARA and CleanSpark also lower. The S&P 500 fell 1.1% and the Nasdaq Composite 1.9%, their biggest one-day declines since July 29 and July 23. The Dow Jones Industrial Average lost 0.1%.

The miners traded with the AI complex, not with bitcoin. Data center operator CoreWeave fell 16%, AI infrastructure provider Nebius 11% and Oracle 9%. Of the 23 stocks in PRISM's AI Data Center and Infrastructure Index, 21 declined, with an average loss of 7.46%. Bitcoin fell to $81,926 on Bitstamp after the inflation print.

September CPI Came In at 3.7%

US consumer prices rose 3.7% over the 12 months to September, above the 3.6% expected, the Bureau of Labor Statistics reported. All items rose 0.6% on the month, seasonally adjusted. Core inflation, which strips out food and energy, ran at 2.6% over the year and 0.3% on the month.

Energy did the work: up 20.4% over 12 months, with gasoline up 34.2% and fuel oil up 74.2%. The gasoline index alone rose 9.1% in September and accounted for more than half of the monthly all-items increase. The energy index rose 5.2% over the month.

Rates repriced immediately. The US 10-year Treasury yield hit 5.329%, about three basis points from a 24-year high. CME FedWatch put the odds of a 25 basis point hike at the Fed's October meeting at 53.7%, against 22.1% a day earlier; the odds of a second hike in December stood at 50%. San Francisco Fed President Mary Daly said further hikes were likely needed to control inflation but that there was no urgency to act this month.

Sonu Varghese, chief macro strategist at Carson Group, said:

"The only surprise is that investors keep getting surprised by broad-based inflation. And we've yet to see the full impact of higher diesel prices and the AI boom."

The Debt and Contracts Behind the Double-Digit Drops

Cipher Digital (CIFR) filed an 8-K on 13 October covering a proposed private offering of $850 million of 0.00% convertible senior notes due 1 November 2032, with an option for another $150 million. There is no cash coupon. The cost arrives at conversion, and Cipher also expects privately negotiated exchanges of part of its 1.75% convertible notes due 2030 into common shares.

The contracted side is large. Cipher describes the amended Barber Lake lease as $9.1 billion in contracted revenue as of 30 September, including $5.2 billion of incremental rent, on a 20-year base term. It intends to put the note proceeds toward capped-call transaction costs, further equity in Barber Lake, high-performance computing pipeline development, site expansion and general corporate purposes.

IREN runs on $14 billion in committed financing and targets $4 billion in contracted annualized recurring revenue operating by year-end. Its AI Cloud revenue more than doubled sequentially to $70.5 million in Q4 FY2026. In August it disclosed a multiyear cloud contract with a frontier AI lab it could not name. A report tying that customer to Anthropic has not been confirmed by either company.

TeraWulf, the worst performer of the four, states on its own site that it holds a $19 billion Anthropic lease in Kentucky and controls 2.9 gigawatts, with 839 megawatts contracted across five locations.

The transmission is direct. Higher rates raise the cost of the debt these companies use to build campuses, and the market repriced that cost the same morning the CPI table landed.

What Would Change the Read

Friday's September Producer Price Index is the next inflation input. The FOMC meets on 27-28 October, though the exact dates could not be confirmed on a Fed page. The FedWatch odds and Daly's comment are the market's read, not a decision. If the 10-year yield holds near 5.329%, the refinancing math behind every debt-financed campus stays where Wednesday left it. If it slips after the PPI print, the trigger behind the miners' session goes with it.