Escalating attacks on tankers threaten a wider oil shock as investors also confront rising U.S. borrowing costs and mounting fiscal pressures
Oil prices hovered near six-week highs on Monday as escalating attacks involving the United States and Iran disrupted commercial shipping through the Strait of Hormuz, raising the prospect of a more severe energy-supply shock across global markets.
Brent crude futures were down 9 cents, or 0.1%, at $96.19 a barrel by 0822 GMT after earlier reaching $97.93, their highest level since July 24. U.S. West Texas Intermediate crude fell 45 cents to $91.03 a barrel, also close to a six-week high.
Brent gained about 8% last week, while WTI climbed nearly 10%, as U.S. and Iranian forces resumed attacks and concerns grew that the conflict could spill over into commercial shipping.
The latest escalation came Saturday when U.S. forces struck three Iranian oil tankers, according to U.S. Central Command, including one off the coast of Kharg Island, Iran’s main oil export hub.
Iran’s Islamic Revolutionary Guard Corps navy said it had targeted three oil tankers traveling through unauthorized routes in the Strait of Hormuz, as well as three additional U.S. vessels elsewhere. The attacks mark a potentially important change in the risk to global energy markets because commercial shipping is becoming directly entangled in the conflict.
“The Saturday attacks represented a ‘major escalation,’” maritime intelligence firm Marisks said, warning that commercial tankers were increasingly being used as instruments of reciprocal economic pressure.
That development has hit the oil market hard. The Strait of Hormuz is one of the world’s most important energy chokepoints, and a sustained reduction in tanker traffic could transform the current price shock into a much larger supply disruption.
An average of just 10 commodity ships passed through the strait each day over the past 10 days, the lowest level since May, according to data from analytics firm Kpler.
“If tanker traffic begins to slow materially, the market could price in a much larger supply shock. And there are already signs that this is happening,” said Priyanka Sachdeva, head of market insights at Phillip Nova.
Goldman Sachs has warned that crude could rise as high as $120 a barrel if attacks on shipping intensify.
Iran is also preparing to tighten restrictions around the strategic waterway. Mohsen Rezaei, secretary of Iran’s Supreme National Security Council, said a restricted zone would be announced outside the Strait of Hormuz in the coming days, according to Iranian state media.
OPEC+ Holds Course As Supply Risks Increase
Against that backdrop, OPEC+ left its oil-output policy unchanged for October at a meeting on Sunday. The producer group said it needed to agree on new quotas before determining its next production steps.
The decision leaves the market heavily dependent on the actual scale and duration of the shipping disruption. If tanker traffic continues to deteriorate, spare production capacity elsewhere may not be sufficient to immediately compensate for logistical constraints in the Gulf.
The consequences would extend beyond gasoline and diesel prices. A sustained oil shock could feed directly into headline inflation, increase transportation and production costs, and complicate monetary policy for central banks that might otherwise be considering lower interest rates.
That creates a particularly difficult backdrop for financial markets because oil is rising at the same time that long-term government bond yields are already under pressure.
Treasury Yield Faces Critical 4.8% Threshold
The 10-year U.S. Treasury yield now faces a closely watched 4.8% level, with a sustained break above it potentially triggering broader stress across equities, credit and other asset classes, according to Matt Maley, chief market strategist at Miller Tabak.
“We remain concerned about the Treasury market…as rising fiscal deficits, massive debt issuance, and heavy corporate borrowing continue to pressure long-term yields… while Treasury Department jawboning has failed to produce the desired decline in rates (at least so far),” Maley said in a note over the weekend.
A sustained move above 4.8%, which corresponds with the high reached in January 2025, would be significant because it could signal that investors are demanding substantially more compensation to hold long-duration U.S. government debt.
Maley said recent efforts by the U.S. Treasury Department and Secretary Scott Bessent to encourage lower yields have not produced the desired result. Those efforts came as investors held large short positions in Treasuries and summer trading volumes were relatively thin, creating expectations that official comments could help trigger a bond-market rally. Instead, the market’s resilience at elevated yields points to a deeper problem: investors are increasingly focused on the underlying supply of government debt rather than simply reacting to policymakers’ statements.
The U.S. national debt has surpassed $40 trillion, while the federal government continues to run large budget deficits. At the same time, the Treasury market is competing with a heavy pipeline of corporate borrowing for investors’ capital.
More than $8.4 trillion of U.S. government securities are scheduled to roll over between now and the end of the year, according to Maley. September could also become a record month for high-grade corporate issuance, while Goldman Sachs recently raised its forecast for U.S. dollar investment-grade corporate issuance in 2026 to $2.3 trillion.
That combination creates a formidable supply challenge for fixed-income markets.
Rising Yields Threaten Wider Asset Repricing
The concern is not limited to Treasuries.
Michael Chen, general manager of Noah ARK Hong Kong, said a disorderly rise in long-term Treasury yields could force a repricing across assets whose valuations depend heavily on long-term interest rates.
Ultra-long-duration bonds, highly valued growth stocks, commercial real estate and some private-market assets could be particularly vulnerable because higher discount rates reduce the present value of their future cash flows.
Chen said structural pressure on the Treasury market was building as investors demand greater compensation for fiscal risk. He favors gold and hard currencies as longer-term hedges and remains underweight ultra-long-duration Treasuries, while maintaining exposure to quality equities, real assets and physical infrastructure associated with AI, including electricity generation, power grids, energy storage and data centers.
The gap between AI-related investment optimism and rising discount rates is becoming notable for markets. The AI infrastructure boom can support corporate earnings and productivity, but higher Treasury yields raise the cost of financing that investment and reduce the valuation investors are willing to assign to future profits.
Global Bond Markets Face The Same Fiscal Problem
The pressure is also spreading across developed economies.
HSBC has become more cautious on long-dated government bonds and raised its end-2026 forecast for the 10-year U.S. Treasury yield to 4.65% from 4.30%, citing a higher structural floor for long-term yields and a more hawkish range of potential monetary-policy outcomes. The bank also raised its end-2026 forecast for 10-year German Bund yields to 3% from 2.8% and said it remains cautious on long-end bonds across developed markets.
Japan, Britain and France face their own fiscal challenges, suggesting that the pressure on government bonds is not simply a U.S. phenomenon.
For investors, the combination of higher oil prices and elevated bond yields is particularly uncomfortable. Oil threatens to revive inflation, while higher long-term yields tighten financial conditions even without additional central-bank rate increases. Analysts warn that this could leave policymakers confronting a familiar but difficult combination of slower growth and renewed price pressures.
Maley cautioned that the Treasury market could still stage a sharp near-term rally.
Bearish positioning is already elevated, and any deterioration in economic data or geopolitical developments that trigger a flight to safety could push investors back into government bonds and temporarily lower yields.
But he argued that such a move would not necessarily represent a reversal of the longer-term trend. The market’s psychological thresholds have already moved progressively higher, from 4.4% to 4.5%, 4.6% and 4.7%, as investors adjusted to persistently high debt issuance and fiscal concerns.
“If we get a bounce in the Treasury market soon (and thus a drop in yields)…and even if it can last through the mid-term election…it’s not something that can be softened over the longer-term…without some serious changes on the fiscal front,” Maley said.
That leaves markets facing two potentially reinforcing sources of pressure. A further escalation around the Strait of Hormuz could push crude toward $100 and beyond, reviving inflation risks just as investors are demanding higher yields to absorb unprecedented volumes of government and corporate debt.
If both trends persist, the result could be a broad tightening in global financial conditions, with consequences for equities, credit, real estate and other risk assets.
