That's a great question — the bond market selloff (rising yields) is one of the biggest stories in markets right now. Let me pull up what's driving it.The bond selloff isn't one story — it's several hitting at once. Here's the breakdown of what's driving it:
1. Oil Shock / Iran War — The Proximate Trigger
Brent crude surged 7% on Thursday (July 24), breaking above $100/barrel after the Iran ceasefire collapsed and reports emerged of attacks on Saudi shipping vessels. Oil and long-term bond yields have been highly correlated since the Iran conflict began in late February. Higher oil → higher inflation expectations → higher yields. The 10-year has been above 4.5% (what strategists call the "danger zone") and hit 4.71% — its highest since January 2025.
The 2-month Treasury yield spiked 13 basis points in a single day to 3.95%, pricing in a legitimate chance of a rate hike at the July 28-29 FOMC meeting. Markets are now putting ~36% probability on the Fed hiking.
2. Fiscal Deficits / Debt Supply — The Structural Problem
The US national debt is now $39.6 trillion, with a debt-to-GDP ratio above 100% for the first time since WWII. The Iran war has cost ~$37.5 billion so far, with another $67 billion in supplemental funding requested. Meanwhile, tariff revenues have collapsed after the Supreme Court struck down much of Trump's tariff authority — the Treasury has already issued $70 billion in refunds. Entitlement outlays are up 7% YoY, including a 10% jump in Medicaid.
The CBO's February projections assumed a 10-year yield averaging 4.1% in 2026. Every 0.1pp above that costs taxpayers roughly $379 billion in additional interest over a decade. At 4.7%, that's a ~$1.8 trillion unplanned hit.
3. AI Capex / Corporate Bond Supply — The Crowding-Out Effect
This is what makes this selloff different from past ones. Six tech giants — Microsoft, Amazon, Alphabet, Nvidia, Meta, and Oracle — have a combined ~$500 billion in outstanding bonds, issuing heavily to fund AI data center builds. Alphabet alone just raised its capex by another $15 billion this year. These corporate bonds offer investors high-quality alternatives to long-dated Treasuries, directly competing for the same pool of capital. As Axios put it: "Governments are running larger deficits just as companies embark on the biggest investment boom in decades — competing for the same pool of money."
4. Waning Foreign Demand
Foreign buyers' share of the Treasury market has been declining for decades, just as issuance needs are exploding. Wellington Management noted that a "handoff" to domestic buyers is needed — but domestic investors may only step in if equities sell off first.
5. New Fed Uncertainty
Kevin Warsh, the new Fed Chair, has scrapped forward guidance and told markets to figure it out themselves. He's signaled he'll use bond market moves as a direct input to policy. The old playbook of "the Fed has your back" no longer applies, and that uncertainty is adding a risk premium to long duration.
The bottom line: This isn't just about inflation fear — it's a regime change. The era of structurally low rates appears over, replaced by a world where finite capital competes with seemingly limitless demand from governments waging wars and companies building AI. As one strategist put it: if long-end demand keeps thinning while issuance rises, 5% on the 30-year stops being a ceiling and starts being a floor.