Iran, Oil and a Hawkish Fed: Why the Dollar Is Winning the Week and Losing the Decade
| TODAY’S NUMBERS 99.73 Dollar Index (DXY) · 4.81% US 10-year Treasury yield · $4,304 Gold, per ounce All three are rising together — the market pricing a Fed rate hike into a war, not a slowdown, a combination not seen in years. |
THE HOOK
Late Monday, Donald Trump signaled the ceasefire with Iran was effectively over, threatening fresh strikes and casting doubt on the reopening of the Strait of Hormuz. Brent crude jumped past $90 a barrel. By Wednesday morning, the US Dollar Index had climbed to 99.73 — its highest in nearly three weeks — and the 10-year Treasury yield touched 4.81%, just shy of a 52-week high. The reason: traders now put the odds of a September Fed rate hike near 65–70%, not a cut.
THE MECHANISM
The chain runs cleanly enough to name. Iran’s conflict with the US raises the odds of a shipping disruption through Hormuz, which carries roughly a fifth of global oil supply; oil-price risk feeds straight into headline inflation; and a Fed under Chair Kevin Warsh — already fighting credibility questions after an ambiguous hold in July — cannot afford to look soft on prices while a war pushes them up. That is why futures markets have swung from pricing no move in 2026 to pricing a hike at the September 15–16 meeting.
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Higher US rates make dollar assets pay more relative to everywhere else, which is the direct channel behind both the stronger DXY and the 4.81% ten-year. The winners are near-term and narrow: holders of short-dated Treasury bills, whose yields rise with the policy rate; US money-market funds; and, oddly, the stablecoin issuers whose reserves sit almost entirely in T-bills and now earn more for holding them. The losers are broader and slower-moving: emerging markets carrying dollar-denominated debt face a double bill, since a stronger dollar raises the local-currency cost of repayment at the same moment their own borrowing costs rise in sympathy with Washington’s. Oil-importing economies — India, Turkey, Japan, the eurozone — take a second hit, paying more for crude in a currency that is simultaneously getting more expensive to buy. Gold, meanwhile, is caught between two forces: safe-haven demand from the war pulls it up, rate-hike expectations pull it down, which is why it sits near $4,304, off its recent peak but still up 21% over the year.
WHY IT MATTERS
The apparent contradiction — dollar strong this week, dollar weaker for the decade — is really two different clocks running at once. Reserve managers make multi-year diversification bets; traders react to a war in hours. The IMF’s COFER data put the dollar at 57.13% of allocated reserves in the first quarter of 2026, down from 72% in 2000, and a recent survey of reserve managers found roughly three-quarters expect that share to keep falling over the next five years. None of that is undone by one hawkish week from Kevin Warsh.
What is new is where the dollar’s reach is actually growing: not in central bank vaults but in stablecoins. The GENIUS Act framework — now the subject of a Treasury rulemaking comment period that closes in October — has pushed issuers to back their tokens almost entirely with short-dated Treasuries, and forecasts from Standard Chartered and Senator Bill Hagerty put potential T-bill demand from stablecoins as high as $2–2.3 trillion. That is dollarization happening retail-first, in emerging-market wallets and crypto exchanges, invisible to COFER. For Washington, a Fed hike timed to a war raises borrowing costs precisely when the deficit needs cheap financing, and when the countries least able to absorb dearer dollars — many of them US partners, not adversaries — get hit hardest. That is a form of collateral leverage no sanctions list ever names.
WATCH FOR
The September 15–16 FOMC meeting is the date that resolves this. A 25-basis-point hike would confirm markets are right to treat this as an inflation fight, not a growth scare, and would likely push the dollar and yields higher still. A hold — especially if Hormuz tensions ease and oil retreats from $90 — would suggest Warsh blinked, and could send gold back toward its highs faster than the dollar can catch up. Either way, watch the Fed funds futures curve shift in the two weeks before the meeting.












