August ended the way most of it was fought — with the Strait of Hormuz setting the price of everything else.
Oil prices surged nearly 3% Monday after the United States and Iran exchanged fire for the first time in a month, and the energy move rippled straight through to bonds and equities. The 10-year Treasury yield rose 4 basis points to 4.76%, its highest intraday level since January 2025, while the 30-year added 5 basis points to 5.26%. Stocks and bonds fell together, the signature of an inflation scare rather than a growth scare.
The Dow Jones Industrial Average dropped 374.09 points, or 0.70%, to 53,185.90, dragged by Goldman Sachs and Alphabet. The S&P 500 fell 0.33% to 7,686.14 and the Nasdaq Composite slipped 0.12% to 26,370.89. Ten of eleven S&P 500 sectors finished lower, with energy and consumer defensives the exceptions.
Yet the month itself was a good one. The S&P 500 gained 2.6% in August and the Nasdaq 3.9% — first monthly advances since May for both — while the Dow rose more than 1% for its fifth consecutive monthly gain and its fifteenth positive month out of sixteen.
Index Performance
Rates, Dollar, Commodities
Larak Island and the Return of Kinetic Conflict
US Central Command confirmed that American forces struck two rocket launchers on Iran’s Larak Island in the Strait of Hormuz on Sunday — the first publicly acknowledged US strike on Iranian positions since late July. Iranian state media reported that Tehran retaliated by attacking US bases in Jordan.
The escalation widened Monday. Iran launched a drone at the United Arab Emirates, which its Ministry of Defence said was intercepted over territorial waters. Abu Dhabi strongly condemned the attack, called it a dangerous escalation, and reserved the right to respond — a notable development given the UAE had already suspended all trade and financial dealings with Iran earlier this month.
The market response was mechanical. WTI settled up 2.83% at $85.76 a barrel and Brent gained 2.71% to $90.49. Higher energy costs feed directly into headline inflation, which feeds into the case for a September rate hike, which pushes yields higher — and higher yields compress valuations for the long-duration growth stocks that have led this market all year. Gold, unusually, did not act as a haven, with futures falling 0.64% to $4,466 as the rate impulse dominated.
The conflict has now passed the six-month mark.
Warsh’s Shadow
Monday’s yield move did not happen in isolation. Kevin Warsh’s Jackson Hole debut on Friday, where he emphasized that restoring price stability remains the Federal Reserve’s predominant focus, had already shifted market pricing toward a September hike rather than a hold.
Oil arriving on top of that message compounds it. The Fed chair has told the market he prioritizes inflation; the oil market has just handed him more of it. That combination is why the 10-year reached levels last seen in January 2025 on a day when equities barely moved — the rate market is repricing policy expectations faster than the equity market is repricing earnings.
Bessent at the G20: Pressure Without Regime Change
Treasury Secretary Scott Bessent opened a meeting of G20 finance ministers in Asheville, North Carolina, on Monday, and used the platform — along with an Associated Press interview Sunday — to make the administration’s case for economic strangulation over military escalation.
His framing of Sunday’s exchange was pointed. “I would think that they are lashing out kinetically because they are losing economically,” Bessent said. Asked how long until Iran’s economy collapses, he offered a timeline and a caveat: “I think it could be within weeks or months — and the economy doesn’t have to collapse, we just have to have the regime come to their senses.”
That distinction matters. The stated objective is not regime change but capitulation to negotiation, with the conditions being abandonment of the nuclear program, return of highly enriched uranium, an end to proxy support, and reopening of the Strait of Hormuz. He announced plans to sanction an additional bank, and said the European Union had backed the campaign with “fulsome support” — the EU confirmed Sunday it welcomes added economic pressure.
On oil supply, Bessent pushed back on scarcity fears with arithmetic: roughly 1.5 million barrels per day of Gulf exports are Iranian, while Saudi Arabia and the UAE have redirected shipments through alternative routes. The implication is that the market has more available supply than the price suggests.
Several of his other comments carry direct market relevance.
On the Treasury market, he said he shares Warsh’s assessment and argued that US government debt has been the strongest performer among major sovereigns, dismissing crisis narratives. On the Treasury’s own role, he was careful: the department’s job is not to dictate the direction of rates or engineer a market equilibrium, but to signal appropriately so that positioning doesn’t become one-sided and prices reflect fundamentals — consistent with how he framed the buyback expansion earlier this month.
On the argument that enormous AI infrastructure investment is crowding out other borrowers, he offered the most contrarian view of the day: that the same investment will produce a productivity boom, and that within three to six months it could become disinflationary rather than inflationary. That directly contradicts the position several FOMC participants took in the July minutes, where they judged AI to be increasing aggregate demand with broadening price effects.
On September policy, he declined to be specific but framed current inflation as an energy supply shock, noting that core inflation remains stable and that central banks typically do not respond to supply shocks with rate hikes unless second-round effects appear. That is a considerably more dovish reading than the market took from Warsh three days earlier — and worth watching as a possible tension between the Treasury and the Fed.
On the yen, he said policy cannot artificially reset an equilibrium exchange rate but can signal, and predicted that Japanese government and Bank of Japan measures will ultimately produce a stronger yen.
Not everyone at the meeting shared the optimism. France’s finance minister Roland Lescure said the world economy is “a bit like the weather in Asheville — it’s unpredictable, it’s foggy,” and hoped for a joint G20 statement on growth. Daniel Fried, a former assistant secretary of state, cautioned that securing international support would require the administration to “take greater care in consulting with allies and partners than the US has shown in recent months.”
Beijing offered its own note. Foreign Ministry spokesman Lin Jian said China would “take all necessary measures to firmly safeguard its own rights and interests” — the standing signal that secondary sanctions touching Chinese entities would not go unanswered.
Around the Market
Alphabet fell 2.49%, one of the Dow’s largest drags, with Amazon down 1.69% and Boeing off 1.34%. On the other side, Chevron rose 2.84% as energy outperformed, joined by Walmart and Cisco.
Tesla advanced ahead of Thursday’s Cybercab launch event in Austin, Texas — a rare product catalyst in a week otherwise dominated by macro.
Strategy drew attention after announcing it had resumed Bitcoin purchases.
August’s leadership is worth recording as the month closes. The S&P 500 technology sector gained more than 6%, with Nvidia up roughly 10%, Microsoft more than 9%, and Micron more than 16%. Moderna finished as the index’s single best performer for the month following its Phase 3 melanoma result.
The Week Ahead
The calendar turns dense again. Manufacturing and services surveys arrive through the week, offering a read on whether August’s four-year high in business activity held. Dell and Broadcom report earnings, with Broadcom particularly consequential given the questions raised when Google brought Marvell into its TPU supply chain.
Everything, though, points to Friday’s employment report. July payrolls fell 23,000 with unemployment at 4.1%. Another weak print, landing while the market prices elevated odds of a September hike, revives the least comfortable framing available: a central bank tightening into a slowdown, with oil supplying the inflation and the consumer supplying the weakness.
Bottom Line
Monday was a compact demonstration of the loop that has governed this market since February. Strikes resume, oil rises, headline inflation risk rises, yields rise, valuations compress. Nothing about corporate fundamentals changed — Nvidia’s blowout quarter is four sessions old — but the discount rate moved, and that was enough.
The interesting tension is now inside the administration itself. Bessent argues that AI investment turns disinflationary within six months and that supply shocks don’t warrant rate hikes. Warsh, three days ago, said price stability is the predominant focus. Both cannot fully govern the September decision, and the gap between them is roughly the gap between a market pricing a hold and one pricing a hike.
Friday’s jobs report gets the next word.
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