Why Oil and Bond Markets Got Shaken Up Over the Strait of Hormuz

Interest rates on U.S. government bonds went up the week of August 10, 2026, because hopes faded for a deal to reopen a key shipping route called the Strait of Hormuz. Oil prices jumped 5% that same week, and bond markets reacted to the higher oil prices (WSJ). The reversal ends a volatile week in which the Trump administration's optimism about an imminent agreement had briefly driven oil prices lower (CNBC.

A quick primer: when you buy a U.S. government bond, you're lending money to the government, and it pays you interest. The interest rate on that bond is called the "yield." When yields go up, it usually means investors are worried about inflation or demanding more compensation for risk. The Strait of Hormuz is a narrow waterway between Iran and Oman through which about a fifth of the world's oil supply passes. When it's threatened, oil prices tend to rise.

The swing from optimism to disappointment played out over several days. Treasury Secretary Bessent said on August 5 that a deal to reopen the Strait could come "today or tomorrow," which pushed oil prices down (WSJ). Qatar separately reported that mediators had made progress in efforts to end the U.S.-Iran conflict, with Iran's Baghaei describing talks with Oman over Hormuz shipping lanes as continuing and "positive" (Reuters). The enthusiasm did not last. By August 10, Iran's latest demands for reopening the waterway had dampened hopes for stability in global markets (Al Jazeera).

At the center of the diplomatic effort is a proposed agreement between Iran and Oman that would end five months of war by giving Tehran control over ships entering the Gulf through the Strait of Hormuz (Reuters). Oman had previously presented Iran with a Gulf-state-backed plan to manage the waterway, which included collecting voluntary fees for transit (Reuters. Iran stated on August 9 that the Oman deal was in "final stages" but insisted the U.S. must act to open the waterway (Reuters. A day earlier, Iran had cautioned that while a deal with Oman was close, it would not be enough by itself to free up the strait (Reuters.

The dollar remained relatively stable through the period. It was supported by safe-haven demand, which is what happens when investors flock to the U.S. dollar during times of global crisis. Military hostilities in the Middle East escalated further (WSJ. The conflict, now in its fifth month, has kept demand for the dollar strong even as bond yields have swung sharply on shifting diplomatic headlines.

This is not the first time during the conflict that bond markets have reacted to a lack of progress in U.S.-Iran talks. Yields changed little in an earlier session when there was no visible progress in negotiations, while oil prices rose nearly 2% (WSJ. The pattern has been consistent: each round of diplomatic optimism draws oil lower and bond yields softer, only for Iran's conditions or the lack of U.S. follow-through to reverse the trade.

In simple terms, here is why this matters for your money. When oil prices go up, things cost more to make and ship. That raises inflation, which is the general rise in prices over time. Investors who lend money to the government by buying bonds then demand higher interest rates to make up for the fact that the money they get back will buy less. The 5% oil price move this week is large enough to show up in those expectations.

Whether bond yields stay higher depends entirely on whether the Oman deal collapses or just stalls. Iran's signal that the Oman deal alone is not enough is the detail worth watching. It means that even a signed agreement would require a separate U.S. commitment to clear the waterway, adding a second layer of uncertainty. Markets had bet on a quick resolution after Bessent's August 5 remarks. Iran's subsequent demands forced investors to rethink that bet. The gap between diplomatic optimism and actual results has been the defining feature of this conflict for bond traders, and this week was no exception.