The Nasdaq fell 1.55%, while the Philadelphia Semiconductor Index plunged 4.78%. SanDisk tumbled more than 12%, SK Hynix ADRs dropped over 9%, Arm lost more than 7%, and Intel declined over 6%. The market action on July 13 was brutal. On the surface, the selloff appeared to be driven by escalating U.S.-Iran tensions pushing oil prices higher, hawkish remarks from the Federal Reserve weighing on the bond market, and concerns over debt-funded AI capital spending dragging down semiconductor stocks. In reality, however, the crack first emerged in the bond market.

Oil Prices Surge, Waller Turns Hawkish, Treasury Yields Spike

President Donald Trump declared, "We will take control of the Strait of Hormuz, and Iran has nothing." Iranian state television responded that the Strait of Hormuz would remain closed until the United States ceased its intervention. U.S. Central Command announced that it had completed a new round of offensive strikes against Iran, using precision-guided weapons to hit dozens of targets. Iran responded by launching drones and missiles from multiple locations across the country, carrying out large-scale attacks against U.S. military targets in the Gulf region. As a result, WTI crude oil futures surged 9.42% to settle at US$78.14 per barrel, while Brent crude futures jumped 9.59% to US$83.30 per barrel, marking the largest single-day gains since May 2020.

The immediate consequence of soaring oil prices was a sharp repricing of inflation expectations. Higher energy prices, combined with the ongoing AI investment boom and tariff-related pressures, are forcing traders to reassess the Federal Reserve's interest rate path. Interest rate swap markets now indicate that investors have almost fully priced in a September rate hike, compared with a probability of just 66% one week earlier.

At the same time oil prices were surging, Federal Reserve Governor Christopher Waller delivered a more hawkish-than-expected speech in New York. He stated that if this week's core inflation data comes in hot again, the Federal Open Market Committee (FOMC) may have to consider tightening monetary policy in the near future. Waller stated bluntly, "By virtually every measure and every standard, inflation has risen this year. Right now, my concern is the persistence of elevated core inflation." He added that policymakers would need to see several months of declining core inflation before they could be confident that prices were moving in the right direction.

Waller's remarks triggered a sharp market reaction because investors had expected the Fed to remain patient despite the inflation shock caused by rising energy prices. According to the CME FedWatch Tool, markets now price the probability of a July rate hike at nearly 50%. The probability of rates remaining unchanged in July stands at 58.3%, while the probability of a cumulative 25-basis-point hike is 41.7%. By September, the probability of a cumulative 25-basis-point increase has climbed to 51.2%. Federal Reserve Chair Kevin Warsh is scheduled to testify before Congress on July 14 and 15. Should Warsh adopt a more hawkish tone, expectations for further rate hikes could strengthen even more.

The combination of soaring oil prices and the Fed's hawkish rhetoric immediately pressured the U.S. Treasury market, sending yields sharply higher across the curve. The 2-year Treasury yield rose 7.2 basis points to 4.286%, the highest level since February 2025. The 3-year yield climbed 7.3 basis points to 4.321%, the 5-year yield rose 7.1 basis points to 4.379%, and the 10-year Treasury yield increased 6.3 basis points to 4.626%. The yield curve experienced a bearish flattening, with short-term yields rising faster than long-term yields—a classic sign that markets are pricing in stronger expectations of further rate hikes.

The rise in the 10-year Treasury yield to 4.626% represents a structural increase in the discount rate used to value technology stocks. For growth companies that depend heavily on future cash flows, this creates significant valuation pressure.

The Bond Market Crack Is the Real Trigger

While surging oil prices and the Federal Reserve's hawkish stance served as the immediate catalysts, the AI sector's sharp decline was fundamentally driven by structural cracks in the bond market. The scale of AI-related debt issuance has reached the market's absorption limit.

According to Dealogic, six AI hyperscalers—Alphabet, Amazon, Meta, Oracle, Nvidia, and SpaceX—have issued approximately US$244 billion in bonds globally this year. That is more than double last year's total issuance of US$108 billion and more than fourteen times the US$17 billion issued in 2024.

Goldman Sachs investment-grade bond trader Jeffrey Papai wrote in a recent report, "Over the past month, AI-related bond issuance has reached US$75 billion, widening spreads in our AI bond basket by approximately 25 basis points." More importantly, the market's capacity to absorb new issuance is declining rapidly. Papai noted, "Previously, it took more than US$75 billion of supply to put pressure on the market. Now, just US$25 billion is enough to push the market into a defensive position."

Meanwhile, leverage is rising at an alarming pace. Morgan Stanley estimates that the average leverage ratio among hyperscalers has surged from 0.9x in the third quarter of 2025 to 1.8x today, doubling in just over two quarters. This now exceeds leverage levels across the energy sector and continues to increase by roughly 0.3x each quarter.

From a market-weight perspective, Amazon, Meta, Google, Microsoft, and Oracle now account for approximately 4% of the U.S. dollar investment-grade corporate bond index. On a duration-weighted basis, six hyperscalers together with three major semiconductor companies now represent roughly 9% of the index. This means price movements in AI-related bonds are now significant enough to influence the broader investment-grade bond market.

Oracle provides a clear example. The company's credit rating has been downgraded to BBB-, just one notch above junk status. On July 9 (U.S. Eastern Time), S&P Global lowered Oracle's credit rating to BBB-. The primary reasons were elevated capital expenditure, growing debt levels, and increasingly strained free cash flow. Oracle continues to invest aggressively in data center expansion while growth in its traditional business slows, weakening its financial resilience. Since early June, its share price has fallen by more than 40% in just over a month.

Oracle's case highlights a broader risk. The AI infrastructure arms race is forcing companies across the industry to continue investing enormous amounts of capital to expand computing capacity. These unavoidable capital expenditures continue to erode profitability. Combined with a high-interest-rate environment, financing costs are rising sharply as companies become increasingly dependent on debt issuance. A credit rating downgrade further raises borrowing costs, creating a negative feedback loop of lower credit ratings, higher financing costs, and deteriorating cash flow.

The Logic Chain: How the Bond Market Triggers the Stock Market

The complete AI investment logic is straightforward: technology giants issue debt, invest heavily in data centers, drive demand for computing power, and in turn lift semiconductor and AI-related stocks. Now, the very first link in that chain is beginning to break.

When the bond market becomes unwilling to continue financing AI-related debt, technology giants will face three choices: slow capital expenditure, accept higher financing costs, or turn to equity financing. None of these outcomes is positive for AI stocks. Slowing capital expenditure would reduce demand expectations for upstream chips and memory. Higher financing costs would erode profits. Equity financing would dilute existing shareholders.

More importantly, the transmission can happen quickly. As AI-related bonds fall in the secondary market and credit spreads widen, financial institutions holding those bonds will face mark-to-market losses. To offset those losses or reduce risk exposure, they may be forced to sell equities. This is the transmission mechanism by which cracks in the bond market can turn into an earthquake in the stock market.

The market selloff on July 13 was, on the surface, triggered by soaring oil prices and hawkish comments from the Federal Reserve. But beneath the surface, the deeper issue is that the bond market is already under significant strain. The US$244 billion of bond issuance by six AI giants this year has pushed the investment-grade bond market close to its absorption limit. Oracle's downgrade to BBB-, SpaceX's 30-year bond yield rising to 7.3%, and Goldman Sachs' credit trading desk describing conditions as "brutal" all point to the same conclusion: the debt-financed model behind AI capital expenditure is approaching a critical tipping point.