S&P 500 briefly turns green after U.S. Hormuz blockade

The S&P 500 erased early losses and briefly turned positive on April 13 as the U.S. began enforcing a naval blockade of Iranian ports in the Strait of Hormuz, U.S. Central Command confirmed the operation was active at 10 a.m. ET.

The intraday reversal followed sharp overnight declines after President Trump announced the blockade following the collapse of talks in Islamabad. Negotiations reportedly broke down over disagreements about uranium enrichment, support for proxy groups and sanctions relief. Equity futures fell overnight before the market’s midday recovery.

Central Command said the blockade targets vessels entering or departing Iranian ports but does not impede transit to non-Iranian destinations. Iran had been exporting more than two million barrels per day before the operation. Brent crude rose above $104 a barrel on supply concerns, and U.S. retail gasoline prices were forecast to climb past $4.25 per gallon.

Shipping data show traffic through the Strait of Hormuz remains well below normal levels despite a slight weekend uptick. The waterway typically handles roughly 20% of global seaborne crude flows, so reduced traffic has driven concern in oil markets.

Reports that Iranian officials were studying whether to abandon uranium enrichment as a condition for ending hostilities helped the equity rebound; Tehran has not confirmed those reports. Market participants said the short-term path for equities will hinge on any interdiction events at sea and on developments in diplomatic channels.

JPMorgan Chase strategist Mislav Matejka recommended buying the pullback, arguing that conditions favor adding risk over a three- to 12-month horizon. The firm forecast a V-shaped recovery within that timeframe and cited potential relative strength in international stocks, emerging markets, small caps and value sectors as oversold signals create opportunities.

Cryptocurrencies and other risk assets showed resilience during the episode. Bitcoin traded above $71,000 as traders continued to absorb geopolitical shocks in recent sessions.

Mohammad Bagher Ghalibaf, speaker of Iran’s parliament, warned that pump prices would rise once the blockade fully affected supplies, writing: ‘Enjoy the current pump figures. With the so-called ‘blockade’, soon you’ll be nostalgic for $4–$5 gas.’

The Strait of Hormuz is a narrow chokepoint linking the Persian Gulf to the Gulf of Oman. Disruptions there tend to move oil markets because a significant share of seaborne crude passes through the strait.