Oil Prices Fell Ahead of U.S. Iran Sanctions. Here’s Why the Supply Risk Remains

Oil prices slipped about 1% on Monday as investors took profits after weeks of gains and waited for details of the U.S. sanctions package Treasury Secretary Scott Bessent was expected to announce at 2 p.m. EDT. The market appeared to have priced in at least part of the escalation, but that did not remove the possibility of a further supply squeeze if the measures are broad and enforceable. 10

Brent and WTI both fell about 1%

In a later Monday trading snapshot, Brent crude futures were down 94 cents, or 1%, at $93.45 a barrel. U.S. West Texas Intermediate futures fell 92 cents, or 1.06%, to $86.14. 10

Earlier in the session, Brent had been down $1.22, or 1.29%, at $93.17, while WTI was down about $1.20, or 1.38%, at $85.86. The different figures reflect the price movement at different points in the session rather than a contradiction in the direction of trade. 8

Why traders sold before the announcement

The immediate explanation was positioning. Brent and WTI had posted their second consecutive weekly gains the previous week, rising by more than 5% as U.S.-Iran peace prospects weakened and oil shipments through the Strait of Hormuz remained heavily restricted.

Investors also had advance notice that Washington planned a major sanctions escalation. Bessent had described the measures as unprecedented, while President Donald Trump warned that countries providing Iran with an economic “lifeline” could face consequences. With the policy direction already public, traders had less reason to buy crude solely on the headline risk before seeing the precise enforcement details. 12

That helps explain the market’s reaction: some traders locked in profits, while others waited to assess whether the final measures would materially remove additional Iranian barrels from the market.

The supply risk behind the elevated prices

The decline came against a backdrop of persistent disruption, not normal market conditions. Nearly six months into the U.S.-Iran confrontation, hopes for a diplomatic breakthrough had faded, Middle East oil output remained curtailed and shipping through Hormuz was severely disrupted. Only seven commodity vessels crossed the strait on the prior Thursday, according to data cited by Reuters.

The market had increasingly begun treating the disruption as prolonged rather than temporary. That shift helped keep crude near $90 a barrel even when individual headlines produced short-term pullbacks.

In that context, Monday’s decline was better understood as a change in expectations and positioning than as proof that the physical supply threat had disappeared.

How the U.S. policy timeline set up Monday’s move

The most important recent policy change was the Treasury Department’s June 22, 2026, 60-day general license authorizing transactions involving Iranian crude, petroleum products and petrochemicals through August 21. The waiver was tied to commitments involving nuclear inspections and free transit through the Strait of Hormuz.

The prospect of more Iranian oil reaching the market helped push oil lower. WTI settled below $74 a barrel after the waiver was announced, while traders expected additional Iranian supply and smoother regional flows.

That relief was temporary. The authorization expired on August 21, removing the supply-supportive signal just before Bessent’s planned announcement. The policy sequence therefore moved from temporary sanctions relief in June to renewed pressure and threatened penalties on Iran’s trading partners in August.

What the new sanctions are intended to do

Washington presented the package as a maximum-pressure campaign designed to isolate Iran economically. Bessent described it as a combination of the existing blockade of Iranian exports and financial and trade measures intended to cut Tehran off from revenue, financing and outside commercial support. He said the goal was to “collapse” the regime and reduce the need for renewed large-scale military operations. 17

Trump’s warning broadened the potential reach beyond Iranian entities. Banks, companies, government bodies and other businesses that provide Tehran with an economic lifeline could face U.S. action, depending on how the measures are implemented. 2

The practical question for oil markets is not only what Washington announces, but also how much of Iran’s remaining trade network it can deter or disrupt.

Why China is central to the oil-market impact

China is particularly important because it buys more than 80% of Iran’s shipped oil, according to 2025 data from analytics firm Kpler cited by Reuters. Washington urged Beijing to cooperate, but China said sanctions and pressure would not resolve the dispute and called for political and diplomatic action instead. 4

If the United States penalizes buyers, banks, insurers, shippers, refiners or intermediaries that continue handling Iranian crude, some participants could reduce or delay purchases to limit their exposure to the U.S. financial system. That would not necessarily destroy the oil physically, but it could make Iranian barrels harder to sell, finance, insure or deliver.

The result could be a smaller pool of crude that is readily accessible to the global market. That is why sanctions can support prices even after an initial sell-off: the market may first react to a measure being priced in, then reprice the physical supply outlook once enforcement begins.

Iran’s response adds another layer of uncertainty

Iran called the threatened measures “economic terrorism” and said its response to new U.S. threats would be “devastating.” Tehran also linked the reopening of the Strait of Hormuz to U.S. concessions, including lifting the export blockade and oil sanctions.

That response leaves two distinct risks for crude traders. Sanctions could restrict Iranian exports through financial and commercial pressure, while continued or intensified restrictions on Hormuz could limit shipments from the wider region. The two effects could reinforce each other if diplomatic efforts fail.

What Monday’s decline really signaled

Monday’s move suggested that traders had already incorporated a significant portion of the expected sanctions escalation into crude prices. It did not establish that the sanctions would have little effect.

The next market test was the scope and enforceability of the package. Measures that reached major buyers and the infrastructure supporting Iranian oil exports could tighten the effective global supply pool and push prices higher. Measures that were narrow, delayed or easily evaded would make the “priced-in” interpretation more credible.

For now, the clearest reading is that oil prices fell because traders sold into a rally and waited for specifics—not because the Iran-related supply risk had gone away.