Stocks Open Lower as Iran Tensions Reignite: First Hour of Trading and Sector Breakdown (Sept 28, 2026)

The Open: Geopolitics Reignite the Risk-Off Trade

After last week’s gains, stocks opened lower Monday as President Trump rejected Iran’s latest ceasefire proposal over the weekend, reigniting the geopolitical risk this week’s market preview flagged as a swing factor for the energy trade. The Dow Jones Industrial Average fell roughly 0.7% in the opening hour, the S&P 500 was down about 0.5%, and the Nasdaq Composite slipped around 0.6% — while the small-cap Russell 2000 held essentially flat, a sign the early selling was concentrated in large-cap and tech-heavy names rather than broad-based. Crude prices surged in response: WTI crude jumped more than 4% to above $96 a barrel and Brent climbed above $108, the same Strait of Hormuz-linked dynamic behind last week’s LNG trade continuing to play out.

EnergySector Performance: Energy Leads, Rate-Sensitive Groups Lag

Energy was the standout sector in the first hour, tracking crude’s surge higher as the market priced in a longer disruption to Middle East supply routes — a direct continuation of the LNG and energy-shock story flagged in this week’s market preview. On the other end, rate-sensitive sectors were among the weakest: utilities and real estate slipped as the 10-year Treasury yield pushed further above 5.2%, its highest level since 2007, raising the effective cost of capital for dividend-heavy and debt-financed businesses. Materials and precious metals also underperformed despite the risk-off backdrop — gold fell more than 3% and silver dropped nearly 5%, as dollar and yield strength outweighed safe-haven buying, a reminder that not every “flight to safety” trade moves the same way when yields themselves are the ones doing the moving.

$NVDATechnology: Mixed Rather Than Uniformly Weak

Technology and semiconductors were mixed in early trading rather than broadly lower. MongoDB tumbled roughly 18% after its CEO’s surprise departure for Meta, and SK Hynix fell about 5% on speculation tied to a possible Solidigm IPO. But Nvidia bucked the sector’s softness, rising nearly 2% on the heels of last week’s record-setting $150 billion buyback authorization and a new AI safety software rollout — a sign that stock-specific catalysts are outweighing sector-wide moves for now even as the broader Nasdaq slipped.

Movers to Watch

What’s Next Today and This Week

The Dallas Fed Manufacturing Index is due at 10:30 a.m. ET, the next scheduled data point that could move sentiment before the closing bell. Looking further out, the earnings calendar picks up quickly: Carnival reports Tuesday, Micron reports Wednesday alongside the advance Q3 GDP reading, and Accenture and Nike both report Thursday. We’ll have full previews and recaps as each name reports — see our Micron (MU) earnings preview, Accenture (ACN) earnings preview, and Nike (NKE) earnings preview for what to expect.