Duke Energy raised $1.75bn in mid-August by selling equity units — a hybrid instrument that pays holders a distribution now and converts into common stock later. The deal closed on 13 August at a 7.75% total annual distribution rate: 2.90% of contract adjustment payments on top of 4.85% interest on remarketable senior notes, with settlement due by 1 August 2029.

That number is worth holding against another one. Duke Energy Carolinas, the utility arm serving the Carolinas, settled its North Carolina rate case at a 9.8% authorized return on equity (ROE) on a 53% equity layer, having asked for 10.95%. The spread between what Duke pays for equity-like capital and what it is permitted to earn on the rate base that capital funds is now about 205 basis points, before tax and before execution risk. Duke serves roughly 8.2 million electric customers across six states and runs the largest regulated capital program in the industry, spending about $1bn a month.

The debt is not the problem

The cleanest public read on what this capital costs sits in a corner of the New York Stock Exchange most equity investors ignore: $25-par notes sold to retail buyers. CMS Energy, the Michigan parent of Consumers Energy with 1.9 million electric and 1.8 million gas customers, has three — 5.625% junior subordinated notes due 2078 and two 5.875% issues due 2078 and 2079. DTE Energy, which supplies about 2.3 million electric customers in southeastern Michigan, has three junior subordinated debentures maturing between 2077 and 2081. Duke has $500m of 5.625% debentures due 2078, deferrable for up to 40 quarters. Entergy Arkansas's 4.875% first mortgage bonds due 2066 are secured, and serve as the control.

At 19 August closes those eight yield between 6.15% and 6.94% on current-yield, with the Entergy secured bond cheapest to the issuer and CMS's 2079 notes dearest. Over twelve months their prices fell about 9.5% on average, deepest at DTE's 5.25% debentures, down 13.2%. Add back roughly six points of coupon and the holder lost about 3.5%.

But the decomposition matters more than the loss. Implied yields on the seven notes with a full year of history rose about 64 basis points. The 30-year Treasury rose roughly 46 basis points over the same window, touching 5.323% on 18 August, a 19-year high, against 4.89% at the end of July 2025. Some 70% of the repricing is therefore the curve. Only about 18 basis points is credit. Breckinridge Capital Advisors puts utility investment-grade spreads at 95 to 105 basis points against a five-year average nearer 105 to 110 — inside long-run norms, even as gross utility issuance runs toward a record, roughly $145bn this year.

The marginal cost of new debt confirms it. DTE issued $1bn of 6.200% junior subordinated debentures due 2058 in June. That is some 370 basis points below the 9.90% ROE the Michigan Public Service Commission granted Consumers Energy in March, and further below still after tax. CMS refiled on 2 June seeking $456m at a 10.25% ROE. Hybrid debt has not converged on authorized returns. Equity has narrowed the gap; debt has not closed it.

Who pays for the data centers

The second leg of the funding question is whether the utility or the customer carries the load-growth capital. Michigan has begun answering. The commission conditionally approved DTE's contracts to supply 1.4 GW to Oracle's Saline Township data center in December, attached protections for other customers, and ordered a large-load tariff filing within 90 days. DTE puts the Oracle contract at roughly $300m a year of benefit to existing customers and a pending 1.0 GW Google deal at about $1.7bn over its life, enough fixed-cost absorption to stay out of a rate case until 2028. CMS estimates its own large-load tariff delivers $7.50 a month of residential bill relief per gigawatt added.

That approval is not finished. Google's special contracts remain under review with a decision expected in September, and Earthjustice appealed the earlier approval to the Michigan Court of Appeals, filing its initial brief on 6 August.

The businesses agree; the shares do not

Duke reported second-quarter adjusted earnings per share of $1.43, up 14%, reaffirmed full-year guidance of $6.55 to $6.80, and carries 7.8 GW of signed data-center energy services agreements with a 15.4 GW late-stage pipeline it expects to convert by mid-2027. Its differentiator is unglamorous and hard to copy: 26 GE Vernova gas turbines on order, the first delivered to Person County in July, with gas supply secured into the early 2030s. It has also said it will not build large nuclear without additional protection against first-of-a-kind risk — a refusal to put construction risk on its own balance sheet.

DTE has 2.4 GW signed and says Oracle and Google alone underwrite "solidly 8%" earnings growth. CMS reaffirmed 2026 earnings per share of $3.83 to $3.90 despite a storm-driven margin hit and introduced 2027 guidance of $4.08 to $4.17, while exiting non-utility renewables and redirecting $1.7bn of that capital into the utility.

Over twelve months CMS shares are down 2.1%, DTE up 0.3% and Duke up 1.2%, against American Electric Power up 11.9% and NextEra up 13.0%. All three flipped decisively lower in the first half of August, their 50-day averages crossing below the 200-day; Duke's turn brackets the eleven sessions around its equity-unit pricing almost exactly.

The de-rating is real. Forward price-to-earnings now sits at 18.28x for CMS, 18.06x for DTE and 18.46x for Duke, against trailing multiples of 20.94x, 21.87x and 18.60x — and against roughly 20.2x to 20.9x trailing for all three in May. On the capital-structure-neutral measures that suit leveraged rate-base businesses, Duke is the cheapest at 11.56x trailing enterprise value to EBITDA and 1.76x book, and the only one of the three with positive trailing free cash flow, at a 1.6% yield; CMS runs at -8.6% and DTE at -6.7% as capex outruns operating cash. Credit, meanwhile, is not deteriorating: Duke targets funds from operations to debt of 14.5% this year rising to 15%, DTE around 15%, against BBB-tier downgrade thresholds nearer 12% to 13%.

The setup

Where it stands — The retail notes fell on Treasury duration, not credit, while the issuers' earnings accelerated and their shares stalled.

Would confirm — Utility investment-grade spreads holding at or inside 105 basis points as 2026 issuance completes.

Would invalidate — A new utility hybrid pricing above 8%, or funds from operations to debt guided below 13%.

Watch next — Michigan's decision on DTE's 1.0 GW Google special contracts, expected September 2026.

Valuation — Duke at 18.46x forward and 18.60x trailing earnings, 11.56x EV/EBITDA, versus roughly 20.3x trailing in May.