Macquarie analysts have warned that a potential agreement between the United States and Iran could increase the risk of oversupply in the oil market by allowing more Iranian crude to reach global buyers.

The firm said such a development could affect the supply-demand balance for Brent crude oil, the global benchmark, which has recently traded in the low-$80s per barrel. Iran’s oil exports have been constrained by US sanctions, so any formal easing of restrictions would be closely watched for its effect on available seaborne supply. A deal could also ease supply concerns linked to the Strait of Hormuz, a major transit route for Middle East crude, and increase oil flows from the region, contributing to a surplus scenario.

Macquarie has revised its Brent crude price outlook lower, forecasting $77 per barrel in 2026 and $64 per barrel in 2027. The adjustment reflects expectations that additional regional supply could become available if US-Iran negotiations lead to a formal agreement.

The analysis indicates that markets appear consistent with a reduced likelihood of crude oil reaching a new all-time high by September 30, based on current pricing. The possibility of greater oil availability has also prompted a recalibration of price forecasts as participants assess the potential impact of increased Iranian output.

Market participants are expected to monitor developments in US-Iran negotiations closely, including whether any agreement changes sanctions enforcement, export permissions, or shipping conditions. OPEC and the International Energy Agency may also provide data, commentary, or policy signals that affect assessments of global supply dynamics, including whether other producers adjust output in response to changing supply expectations.

Geopolitical stability in the Middle East remains a key factor for the outlook. Conditions in the region could either reduce or intensify the surplus risk identified by Macquarie, while the coming months may determine whether crude oil can challenge or approach new all-time highs.