The S&P 500 opened slightly lower or mixed on August 17, 2026, as investors digested ongoing US-Iran tensions alongside a strong revenue forecast from AI startup Anthropic [1, 2, 3]. The index opened at 7,775.01 according to one source or 7,790.68 according to others, reflecting small divergences in reported levels [1, 2, 3].
Dow Jones Industrial Average also opened lower in some reports at 53,567.95, down 0.31%, while other sources showed a smaller decline to 53,663.11, down 0.13%. Meanwhile, the Nasdaq Composite opened flat or slightly up, with figures ranging from 26,726.73 to 26,784.65 depending on the source [1, 2, 3].
Geopolitical risks remained elevated amid concerns Iran could escalate tensions near the Strait of Hormuz, driving some caution in energy and broader markets. David Morrison, senior market analyst at Trade Nation, noted, “(Investors) were telling themselves wars always come to an end. I don't think anyone was pricing in the fact that this could still be going as we approach the end of the summer.” [1]
Despite geopolitical jitters, technology stocks gained support from Anthropic’s revenue forecast. The AI startup, preparing for an IPO, projected revenues between $190 billion and $200 billion in 2028 [1, 2, 3]. Danni Hewson, head of financial analysis at AJ Bell, said the forecast provided “more clarity on AI investments and the source of returns,” easing fears of a potential boom-and-bust cycle in the sector [1].
Energy markets moved higher as well. Brent crude futures climbed about 0.4%, while the S&P 500 energy index rose 0.2%, reflecting the impact of Middle East tensions on oil prices [1].
The market followed a week where the S&P 500 closed at record highs due to softer inflation data and reduced expectations for Federal Reserve rate hikes [1].
Investors will watch closely for any escalation in Middle East tensions as well as progress on Anthropic’s IPO and its impact on tech sector sentiment in coming sessions.
