Oil's 6% plunge lifts Treasury bid as Iran deal hopes grow

The 10-year US Treasury yield fell more than 1 basis point to 4.688% as oil prices plunged over 6% after President Donald Trump called off fresh military strikes on Iran, raising hopes that a diplomatic resolution could reopen the Strait of Hormuz and unwind the geopolitical premium that drove crude up more than 20% in July.

"The bigger focus is whether this week turns into a rinse and repeat of last week — with hopes of a deal collapsing as Iran digs in its heels and continues to leverage its control over the Strait," said Tony Sycamore, market analyst at IG.

West Texas Intermediate crude fell $5.20 to $79.47 a barrel, down 6.14%, while Brent dropped $4.65 to $83.28, down 5.29%. The selloff followed Trump's Saturday statement on Truth Social that Iran and other Middle Eastern countries had asked for time to complete a deal that would lead to the "Immediate, Complete and Total" reopening of the Strait and "an end to Iran's nuclear threat." Two Saudi oil tankers successfully transited the Bab el-Mandeb Strait over the weekend, though the UK Maritime Trade Operations reported three additional tanker attacks since Saturday, showing that maritime risks remain elevated.

The bond market's response reflects the transmission chain: cheaper crude reduces inflationary pressure, supporting fixed-income demand and lowering yields. But the risk cuts both ways — if negotiations collapse, crude could surge again, pushing yields higher as inflation expectations reprice. OPEC+ approved a production quota increase of roughly 188,000 barrels per day for September, completing the unwinding of one layer of its voluntary production cuts, though actual output gains have been limited by disruptions across the region.

The July Premium Unwinds

Both benchmarks surged more than 20% last month after fighting between the US and Iran resumed and attacks on several tankers around Oman heightened security concerns, deterring shippers from entering the Gulf to load oil. The Strait of Hormuz handles roughly 21% of global oil trade, making any disruption to shipping lanes a direct threat to supply. Iranian officials said negotiations with Oman over a new shipping arrangement through the strait are in their final stages, though Tehran has insisted vessels will no longer be permitted to use the previous southern shipping lane off Oman's coast, indicating that even if the strait reopens, shipping patterns could change significantly.

The de-escalation hopes also rippled through currency markets. The Canadian dollar drifted lower against the greenback as falling crude weighed on the commodity-linked currency, offsetting broad US dollar weakness. USD/CAD traded higher as investors weighed softer oil against reduced safe-haven demand. The Australian dollar, another commodity-sensitive currency, held firm as China's manufacturing PMI slightly missed forecasts but remained in expansion territory.

What's at Stake for Rates

For bond investors, the oil price trajectory is a key input into inflation expectations. A sustained decline in crude would support the case for the Federal Reserve to ease policy, potentially pushing yields lower across the curve. Conversely, a renewed escalation that sends Brent back above $90 would complicate the Fed's path and likely lift yields.

The last time oil prices swung this violently on geopolitical headlines was in July, when both benchmarks surged more than 20% in a single month as renewed US-Iran hostilities and a Houthi blockade of Saudi ports stoked fears of prolonged supply disruptions through the Strait of Hormuz and the Red Sea. That episode demonstrated how quickly the geopolitical premium can build — and how rapidly it can unwind when diplomatic signals shift.

If negotiations hold and shipping in the region returns to normal, much of July's geopolitical premium could continue to unwind in the coming weeks. But without a broader agreement, any renewed military escalation or disruption to Gulf exports would likely send crude prices surging higher, testing the Fed's inflation outlook and Treasury yields once again. Traders will be watching for any signs of progress in the Oman-mediated talks and for weekly inventory data to gauge whether the supply picture is tightening or easing.

This article is for informational purposes only and does not constitute investment advice.