Cipher Digital (NASDAQ: CIFR) said on Tuesday, October 13, that it intends to sell $850 million of zero-coupon convertible notes maturing in 2032 — a raise that comes barely three weeks after the company agreed to absorb $359.3 million in cost overruns at its Barber Lake data center in Texas.

The offering is the latest illustration of how former Bitcoin miners are paying for their artificial intelligence buildouts: when construction costs climb, they turn to the convertible bond market, a financing route that has become a staple of the sector's AI pivot.

How the Barber Lake overruns arose

The overruns Cipher is now covering trace back to September 25, when the company announced that Barber Lake's contracted life would be doubled to 20 years. The extension pushed contracted revenue from $3.8 billion to more than $9 billion.

The lease extension was paired with a binding agreement with a leading AI lab — a 10-year commitment expected to generate an additional $5.2 billion in incremental contracted revenue.

The agreements also changed which party bears construction overruns. Under a reimbursement framework published in September 2026, Cipher will absorb the first $359.3 million of cost overruns, while the tenant handles 50% above the original budget; only above that line does the tenant cover half, repaid as extra rent over the 20-year term.

No coupon — and a 2030 exit hatch

The notes will mature on November 1, 2032, and will carry no regular interest. Zero-coupon instruments of this kind let issuers raise capital without ongoing interest payments, with holders compensated instead by the option to convert into equity. Cipher plans to sell the notes privately under Rule 144A to qualified institutional buyers, and initial purchasers will have a 13-day option to buy up to $150 million more, taking the deal to the $1 billion mark.

Cipher also said it plans to exchange some of its remaining 1.75% convertible notes due 2030 for common stock.

Despite the 2032 maturity, noteholders can compel Cipher to repurchase the notes for cash on November 1, 2030, unless those notes have been called for redemption — meaning repayment could come two full years ahead of schedule. Together with the planned swap of the 1.75% notes, the put date marks Cipher's nearest debt-related decision point, well before the 2032 maturity.

Cipher intends to use the proceeds to fund capped-call transactions designed to limit share dilution, pour additional equity into Barber Lake, advance its high-performance computing (HPC) pipeline, add development sites, and cover general corporate needs. Conversions can be settled in cash, stock, or a mix of the two, at Cipher's election. The equity earmarked for Barber Lake ties the new money directly to the overrun burden Cipher agreed to take on under the September framework.

Cipher's share price dropped 9.6% to $11.75 in premarket trading on Tuesday, down from $13. As recently as September 25 — the day the lease extension was announced — the stock traded at $18.74, meaning it has shed more than a third of its value in under three weeks.

A familiar financing playbook

Cipher has been repositioning itself from Bitcoin mining toward AI and high-performance computing data centers, and debt markets have been central to that transition. In September 2025, the company priced roughly $1.1 billion of 0.00% convertible notes due 2031 — an offering originally sized at $800 million that ultimately crossed the billion-dollar mark — with the funds earmarked for Barber Lake and its HPC pipeline.

According to reports, Cipher has also raised $1.73 billion in secured notes carrying a 7.125% coupon to fund Barber Lake, and has earmarked $2 billion for its Black Pearl development.

The approach reflects a recurring pattern across the industry. TeraWulf and IREN closed convertible deals in October 2025 and May 2026, respectively — TeraWulf looking to fund its Texas campus, and IREN looking to expand its AI cloud business. For issuers in the middle of multi-year data center builds, convertibles offer size without near-term cash interest, with the cost surfacing later as potential dilution — a structure matched to contracted revenue streams that, as at Barber Lake, stretch across two decades. Still to come are the offering's final terms, including the notes' conversion price and the cap on the capped-call transactions.