S&P 500 and Nasdaq Hit Fresh Records on Micron Surge and Iran Optimism

CNBC reported Tuesday that the S&P 500 record close was the headline outcome of a broad tech-driven session, with both the index and the Nasdaq Composite reaching fresh intraday and closing highs.

Micron Leads a Broad Tech Advance

The S&P 500 gained 0.61% on the day. The Nasdaq outperformed with a 1.19% advance. The Dow Jones Industrial Average bucked the trend, slipping 118 points, or roughly 0.23%.

Micron Technology shares surged 19%, pushing the chipmaker’s market capitalisation above $1 trillion for the first time. The milestone gave the broader semiconductor sector a significant lift. Investors have been closely watching memory chip demand as an indicator of AI infrastructure spending cycles.

Iran Ceasefire Hopes Add to Bullish Sentiment

Geopolitical relief added further fuel. President Donald Trump signalled that nuclear talks with Iran were progressing constructively. US Central Command also confirmed that American strikes in southern Iran were conducted with restraint, with a ceasefire remaining nominally in place.

Easing Middle East tensions, alongside a resilient corporate earnings season, have underpinned a string of new highs for US equities throughout 2026.

A Record Run With a Cautious Backdrop

Not everyone is convinced the rally has much further to run. Drew Pettit, US equity strategist at Citi, told CNBC’s Power Lunch that the current macro setup limits room for further multiple expansion. He cited the 10-year Treasury yield sitting near 4.50%, stickier inflation expectations, and a flatter yield curve as headwinds. His year-end S&P 500 target of 7,700 implies only a 2% gain from current levels.

After-Hours Movers Complicate the Picture

Post-close trading delivered some notable declines. Zscaler shares fell roughly 19% after the cloud security firm issued current-quarter revenue guidance of $875 million to $878 million, narrowly missing the $879 million consensus tracked by LSEG. Insulet dropped nearly 7% after announcing a voluntary correction for specific lots of its diabetes management pods. Box slipped around 2% after its full-year earnings guidance fell short of analyst expectations.

Stock futures were little changed overnight. Futures on the S&P 500 and Nasdaq 100 each edged about 0.1% lower, while Dow futures shed fewer than 20 points.

Earnings from Dick’s Sporting Goods, Bath and Body Works, Abercrombie and Fitch, and Manchester United are due before Wednesday’s opening bell.

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