On July 28, 2026, a major stock market index called the Nasdaq-100 fell 376.90 points, or 1.34%, to close at 27,662.31. During the day, it briefly dropped into what investors call "correction territory" — meaning it fell about 10% from its recent high point. Think of it like a sale sticker on a product: a 10% drop is significant enough that people in the market start paying close attention. The index hit a low of 27,452.95 before bouncing back somewhat. The close was below the prior session's 28,039.21 and the day's high of 27,814.86, according to Nasdaq.

The correction signal came at roughly 3:07pm ET, per the Wall Street Journal's live coverage, which reported the Nasdaq-100 briefly crossing that 10%-from-peak line. The Nasdaq Composite, a related but broader index, approached correction territory too. Intel and Micron, two big computer chip companies, were the specific stocks pulling the index down (WSJ). Morningstar republished the report at 15:12 ET (19:12 GMT) (Morningstar).

The sell-off was not limited to U.S. markets. The Philadelphia Semiconductor Index (SOX), which tracks major chip companies, also declined on July 28 (Bloomberg). Reuters headlined the session "Nasdaq futures drop on AI chip worries ahead of pivotal earnings," noting that Nasdaq 100 futures were down 194.5 points, or 0.69%, before the market opened (Reuters).

This was not a one-day event. July 2026 has been rough for chip stocks. The SOX had already fallen over 18% for the month as of July 17 (Reuters). On July 16, the SOX fell 4.3%; the Nasdaq posted a 2.9% weekly decline for the week ending July 17 (Yahoo Finance). The Nasdaq Composite dropped 1.4% to 25,520.24 on July 17 (CNBC). On July 27, the day before the correction, the Nasdaq Composite lost 0.18% to settle at 24,932.08, with chip stocks broadly lower before bouncing off their lowest levels (CNBC).

The pattern was visible earlier in the month, too. On July 7, the Nasdaq dropped 1% as chip stocks fell and oil prices rose (CNBC). On July 8, a brief recovery saw the Nasdaq Composite gain 1.30% to 26,206.89 as chip stocks rose and oil fell (CNBC). The volatility goes back further: on June 4, the Nasdaq Composite fell roughly 4%, its worst single-day decline since April 2025 (CNBC). And on May 19, the Nasdaq 100 lost 0.6% after giving up an earlier 1.9% gain, as chip shares surrendered a late-day rebound (Bloomberg).

Two things set off the July 28 sell-off. Bloomberg reported that progress by China's chip industry was unnerving global markets (Bloomberg). Separately, worries about debt tied to artificial intelligence spending contributed to the decline, with Bloomberg noting growing "AI fatigue" — investors growing skeptical about whether all the money being poured into AI will pay off — as a driver behind Korean chipmaker declines that spread worldwide (Bloomberg).

The split within the market was striking. The S&P 500, a broader index of 500 large companies, rose as oil prices fell and gains across other sectors outweighed the chip decline (Bloomberg). The Dow Jones Industrial Average, another major index focused on large, established companies, rallied 575 points on the same day (MarketWatch; WSJ). MarketWatch noted at 2:47pm ET that the Nasdaq 100 was on pace to close lower amid the chip sell-off, about 20 minutes before the WSJ reported the correction (MarketWatch).

The broader context here matters for understanding what moved and why. The Nasdaq-100 briefly entering correction while the Dow rallies over 500 points and the S&P 500 closes higher is a classic sign of sector rotation under stress — investors pulling money out of one area of the market (chip stocks) and shifting it into others. The Nasdaq-100 has a lot of weight in semiconductor companies, particularly Intel and Micron, so bad news for those few companies can drag the whole index down to levels that traders consider significant. The SOX's 18% drop for the month heading into this session made the correction threshold easier to cross; the index was already weakened.

The two triggers — China's chip advances and AI debt worries — point to risks on different timelines. China's progress in semiconductors challenges a competitive advantage that has supported U.S. chip companies' valuations for years. The AI debt concern is more immediate: companies borrowed heavily to fund AI projects, and investors are now questioning whether those projects will generate revenue fast enough to pay back what they owe. Reuters framing this as happening "ahead of pivotal earnings" suggests the market is waiting for company earnings reports to confirm or disappoint expectations. The fact that the index recovered from its lowest point to close at 27,662.31, above the 27,452.95 trough, indicates some investors were still willing to buy on the dip. Whether that buying continues through earnings season is the open question.