Dollar index hits two-week high as rate bets move FX

Dollar index rose 0.11% to 99.76 Wednesday, hitting a two-week high as investors weighed oil risks and rate gaps. The euro fell.

The index, which tracks the U.S. currency against peers including the euro and yen, touched 99.808, its highest level since August 17. The euro slid 0.16% to $1.1575 after reaching $1.1570, its weakest level since August 20.

Oil shock favors greenback

The currency move followed a renewed U.S.-Iran confrontation after the most consequential exchange of fire in weeks. Higher oil prices can support the dollar when investors view the U.S. economy as less exposed to energy costs than Japan or the euro area.

That relative exposure matters for rate expectations. Schroders expects the euro to weaken to $1.10 by year-end, compared with $1.1575 on Wednesday, on the view that rate differentials will move further in the dollar's favor.

The dollar's support is not one-directional. A selloff in U.S. Treasuries can weigh on the currency if investors focus on inflation pressure and the fiscal path rather than yield advantage.

Treasury yields test dollar support

The benchmark U.S. 10-year yield reached 4.812%, its highest level since November 2023, before easing to 4.804%. Higher yields mean lower prices for the note, a signal that investors were demanding more compensation to hold long-dated U.S. debt.

Fed rate pricing also moved toward tighter policy. Markets priced a 70% probability of a September increase, up from about 40% a week earlier, according to CME Group's FedWatch tool.

Yen nears 160 line

The yen gained 0.45% to 159.50 per dollar after earlier weakening to its lowest point since July 31. The move left Japan's currency close to the 160 threshold that traders treat as a test of tolerance for further depreciation.

Japan's benchmark 10-year yield rose to 3.01% on Wednesday after reaching 3% on Tuesday, a level described in the source material as a three-decade milestone. The bond move came as markets assessed how far the Bank of Japan may go in tightening policy.

U.S. Treasury Secretary Scott Bessent supported "decisive" monetary steps to counter yen weakness in a meeting with Bank of Japan Governor Kazuo Ueda, the Treasury Department said. A rare joint U.S.-Japan intervention at the end of July pulled the yen away from a 40-year low of 163.99, though the currency has since given back about half of that gain.

Tony Sycamore, a market analyst at IG, tied the chance of further joint action to the energy backdrop. "There appears little chance of another round of actual co-ordinated intervention until there is some de-escalation in the Strait of Hormuz that takes heat out of the oil price," he wrote in a note.

New Zealand decision disappoints

The New Zealand dollar dropped 1.01% to $0.5844, its lowest level since August 13. The move came even after the Reserve Bank of New Zealand lifted its official cash rate by 25 basis points to 2.75%.

Analysts cited in the source material said investors viewed the decision as less hawkish than expected. That reaction shows how currency markets can punish a rate increase when the accompanying policy signal falls short of positioning.

If oil prices stay elevated, the dollar's relative advantage could persist through inflation expectations, rate pricing and demand for liquid assets. That path would tighten financial conditions globally, support the dollar against energy-sensitive peers, and pressure importers and exporters in currency-sensitive industries.

If energy prices ease or Treasury selling intensifies, the mechanism changes. Lower oil risk would reduce one source of dollar support, while higher concern over U.S. debt or inflation could make Treasury yields less helpful for the currency and give the euro, yen and commodity-linked currencies room to stabilize.