Key Takeaways

• Yields on major US technology bonds rose on Thursday (Friday AEST) as AI debt worries, an oil shock and a rate repricing hit at once.

• Alphabet's 5.5% bonds due 2046 rose about 9 basis points to a 6.11% yield after the company lifted its capital-spending forecast.

• Oracle bonds due 2030 climbed about 17 basis points to roughly 6.09%, while credit default swaps on Microsoft and Amazon were bid higher.

• Rising Treasury yields and US$100-plus oil threaten to raise funding costs for firms pouring hundreds of billions into AI infrastructure.

• Higher long-term yields can pressure rate-sensitive ASX sectors and reprice Australian bond portfolios; markets were closed at the time of writing.

The bonds of America's biggest technology companies slid on Thursday in New York as investors reassessed the debt fuelling the artificial intelligence boom, an oil price above US$100 a barrel and the prospect of higher-for-longer interest rates. The move lifted borrowing costs across the sector and rippled into rate-sensitive markets, including Australia's.

What happened

The debt of some of the largest US technology companies fell on Thursday in New York (Friday AEST) as investors grew more nervous about the scale of borrowing behind the artificial intelligence (AI) build-out, at the same time as an escalating conflict in the Middle East pushed oil above US$100 a barrel.

Rising oil prices have revived inflation concerns. That, in turn, has lifted longer-term bond yields, threatening to increase borrowing costs for companies channelling hundreds of billions of dollars into AI data centres.

A quarterly report from Alphabet, the owner of Google, added to the selling. The company raised its capital-spending forecast, a signal that the flood of new debt financing the AI boom is likely to keep coming.

The yield on Alphabet's 5.5% bonds due 2046 rose about 9 basis points to 6.11%, according to figures reported by AFR Markets Live citing Bloomberg data. That put the yield roughly 91 basis points above the top-rated benchmark, up 6 basis points from Wednesday. Oracle debt due 2030 saw its yield climb about 17 basis points to around 6.09%.

Investors also bid up credit default swaps tied to the debt of Microsoft and Amazon, a sign of heightened concern about credit risk.

"The market is being hit with a triple whammy of AI capex anxiety, oil shock and a rate repricing," said Tony Trzcinka, a portfolio manager at Impax Asset Management.

US markets had closed for the session at the time of writing, and the Australian sharemarket was yet to react fully.

Bonds, yields and prices, explained

A bond is essentially an IOU. When a company such as Alphabet or Oracle borrows money in the bond market, it promises to pay investors a fixed rate of interest, called the coupon, and to repay the face value on a set maturity date.

The yield is the return an investor earns based on the price paid for the bond. Bond prices and yields move in opposite directions. When investors sell bonds, prices fall and yields rise; when they buy, prices rise and yields fall. So Thursday's rising yields mean the prices of these technology bonds fell.

A basis point is one-hundredth of a percentage point. A move of 9 basis points, as seen in Alphabet's long-dated bond, equals 0.09 of a percentage point. These sound like small numbers, but on debt maturing decades from now, even modest yield changes can meaningfully move prices.

Credit spreads and what CDS signal

The figure of "91 basis points over the top-rated benchmark" describes a credit spread. A credit spread is the extra yield investors demand to hold a company's bond instead of a safer government bond or top-rated benchmark of similar maturity. It is the market's price for taking on the risk that a borrower might struggle to pay.

When a spread widens, as Alphabet's did, investors are asking for more compensation, a sign of growing caution about that borrower or the sector.

A credit default swap, or CDS, is a form of insurance against a borrower defaulting. One party pays a regular premium; in return, the other agrees to cover losses if the borrower fails to repay. When the cost of that insurance rises, as it did for Microsoft and Amazon on Thursday, it signals that the market is pricing in more risk, even if a default remains unlikely for such large, cash-generative firms.

The tech-bond issuance wave

The unease has been building for months, driven by an unprecedented surge in borrowing by the technology giants known as hyperscalers.

Through 2025, the largest hyperscalers issued roughly US$121 billion in new bonds, according to Mellon Investments, with more than US$90 billion raised in a single three-month stretch. In October 2025, Meta Platforms sold US$30 billion of bonds in its biggest-ever debt deal, drawing record order books at the time. Oracle and Alphabet have also become frequent issuers, to the point where technology companies have started to rival banks as the dominant borrowers in the US investment-grade market.

The pace has accelerated in 2026. Morgan Stanley has forecast around US$570 billion of AI-related debt issuance for the year, and by late May roughly US$236 billion had already priced, a fourfold jump on the same period a year earlier, per Forbes reporting on the bank's estimates.

Crucially, appetite has started to thin. Earlier in 2026, hyperscaler bond sales were covered around five times over, meaning orders far exceeded the bonds on offer. By July, that coverage had slipped below two times, according to figures cited by Forbes. Weaker demand suggests issuers may have to pay more to borrow. Separately, Bloomberg reported that the cost of insuring Oracle's debt via CDS reached a near-18-year high earlier this week.

The drivers

Three forces converged on Thursday.

The first is AI capital-expenditure anxiety. Investors broadly accept that data centres, chips and power are expensive, but the sheer volume of debt being raised, and Alphabet's decision to lift its spending forecast again, has prompted questions about how much more the bond market can absorb, and at what price.

The second is the oil shock. Brent crude pushing above US$100 a barrel, its first move to those levels in months, feeds directly into inflation expectations. Higher energy costs tend to keep consumer prices elevated.

The third is a rate repricing. Persistent inflation makes it harder for central banks to cut interest rates, so investors demand higher yields on longer-dated bonds. The US 10-year Treasury yield climbed to its highest since early 2025 as oil rose, according to market reports. Because Treasury yields are the reference rate for much corporate borrowing, their rise pushes up costs everywhere.

Implications for global funding costs

For the hyperscalers, higher yields mean the next round of AI financing is likely to be more expensive. Balance sheets remain strong and cash flows are substantial, so these are not distressed borrowers. But if the market keeps demanding wider spreads, the economics of the AI build-out become tighter, and the gap between companies with clear returns on their spending and those still to prove it may widen.

More broadly, when the largest, safest corporate borrowers pay more, the cost of credit tends to reset for everyone lower down the quality scale. Higher benchmark yields feed through to smaller companies, riskier borrowers and emerging markets, all of which typically pay a premium over the giants. That is one reason a technology-led bond wobble can matter far beyond the technology sector.

There is also a supply question. The bond market is being asked to absorb record volumes of new technology debt at the same time that governments in the United States, Europe and elsewhere are running large deficits and issuing heavily. When both corporate and government borrowers compete for the same pool of savings, yields can drift higher simply because there is so much paper to be placed.

What it means for Australian investors

Australian investors are not insulated. Global bond yields tend to move together, so a rise in US long-term yields typically drags Australian government and corporate bond yields higher, which lowers the price of existing bonds. Investors holding longer-dated bonds or bond funds may see the capital value of those holdings fall when yields rise, even as the income they pay stays fixed.

On the sharemarket, rising yields tend to weigh on rate-sensitive sectors. Real estate investment trusts, infrastructure names, utilities and highly valued technology stocks are often the most exposed, because their appeal rests partly on future income that looks less attractive when safer bonds offer higher returns. Higher oil prices can lift local energy producers while squeezing sectors exposed to fuel costs, such as transport.

The Reserve Bank of Australia's own path matters here. With global inflation pressures rebuilding on the back of oil, the local rate outlook could shift, affecting everything from mortgage costs to the Australian dollar.

A balanced view

It is worth separating fact from fear. The verified moves on Thursday were real but measured. A 9-basis-point rise in a 21-year Alphabet bond, or a 17-basis-point move in Oracle debt, is a repricing, not a rout, and the companies involved are among the most creditworthy in the world.

Equally, the trend of thinning demand and widening spreads is genuine and worth watching. Analysts remain divided on whether this is a healthy adjustment to an enormous supply of new debt or an early warning that the market's patience with AI spending is running low.

What Investors May Watch Next

- The trajectory of oil prices and any further escalation in the Middle East, given the direct link to inflation and yields. - US 10-year Treasury yields and credit spreads on hyperscaler bonds as a gauge of funding stress. - Order coverage on the next large technology bond sales, an early read on investor appetite. - Further capital-spending guidance from Alphabet, Microsoft, Amazon, Meta and Oracle. - The RBA's commentary on inflation and rates, and the response of ASX real estate, infrastructure and technology shares.