US stocks did not fall uniformly on July 28, 2026, but the technology-heavy part of the market suffered another sharp setback. The Nasdaq Composite slipped 0.22% and the Philadelphia Semiconductor Index dropped 4.5%, while the Dow Jones Industrial Average gained 1.03% and the S&P 500 added 0.21%. The split tells a more useful story than the headline: investors were rotating out of expensive AI and chip stocks, not abandoning every part of the US market.
The S&P 500 closed at 7,428.78, the Nasdaq at 24,876.91 and the Dow at 52,747.32. Traditional sectors including healthcare, consumer staples and materials rose, helping the broader index withstand heavy selling in semiconductors.
What fell in the US market?
Semiconductor and memory-related stocks were at the centre of the decline. The Philadelphia Semiconductor Index lost 4.5%, extending a pullback that had already pushed it well below its late-June peak. Micron, AMD, Intel, Broadcom, Marvell and SanDisk were among the names under pressure, while Corning fell after its third-quarter sales outlook disappointed investors.
| Market measure | July 28 move | What it showed |
|---|---|---|
| Dow Jones Industrial Average | +1.03% | Strength in industrial, healthcare and consumer names |
| S&P 500 | +0.21% | A mixed market, with non-tech gains offsetting chip weakness |
| Nasdaq Composite | -0.22% | Pressure on technology and AI-linked shares |
| Philadelphia Semiconductor Index | -4.5% | A concentrated sell-off in chipmakers |
AI spending is facing a tougher test
The first concern is the amount of money being committed to AI infrastructure. Investors have rewarded chipmakers, data-centre suppliers and cloud companies for much of the past two years, assuming that spending on servers, networking and accelerators would translate into durable profit growth.
That assumption is now being tested. The largest US technology companies are entering an important earnings period, and shareholders want evidence that their capital expenditure is producing revenue rather than simply creating another expensive arms race. When expectations are extremely high, even solid results or cautious guidance can lead to selling.
Corning illustrated the problem. The company’s optical-communications business has benefited from data-centre construction, but its forward sales forecast was not strong enough to satisfy a market that had already priced in rapid AI-related growth. Its decline added to concerns that suppliers across the AI infrastructure chain may struggle to keep exceeding forecasts.
Chinese competition unsettled semiconductor investors
The second catalyst came from China. The strong market debut of Chinese memory-chip producer ChangXin Memory Technologies, commonly known as CXMT, and reports of progress in domestically produced chipmaking equipment reminded investors that today’s industry leaders may face stronger competition.
CXMT does not need to immediately match the most advanced high-bandwidth memory products to affect the market. Greater Chinese capacity in conventional memory could still pressure prices and margins elsewhere in the industry. Reports of progress in deep-ultraviolet lithography equipment also raised questions about how quickly China could reduce its dependence on overseas semiconductor tools.
These developments do not prove that US chipmakers will lose their lead. They do, however, weaken the idea that the current profit pool will remain protected indefinitely. That is enough to unsettle stocks carrying demanding valuations.
The Federal Reserve added another reason for caution
The sell-off also occurred during the Federal Reserve’s July 28–29 policy meeting. Investors were waiting for the interest-rate decision and the accompanying press conference, with uncertainty heightened by volatile energy prices and inflation risks.
Higher-for-longer interest rates generally weigh most heavily on growth stocks because a larger share of their expected value depends on profits far in the future. Expensive AI companies are therefore especially sensitive to changes in bond yields and rate expectations.
Why did the Dow rise while chips fell?
The Dow benefited from gains in companies such as Boeing and Coca-Cola, while healthcare, staples and materials also advanced. This is known as a market rotation: investors sell one crowded group and move money into sectors with lower valuations, steadier cash flow or less dependence on AI investment.
It is therefore inaccurate to describe July 28 as a broad Wall Street crash. The better description is a severe semiconductor correction inside a mixed US market. That distinction matters because it suggests that investors were reassessing the price and risk of the AI trade rather than reacting to a single economy-wide shock.
What investors will watch next
The next signals will come from major technology-company earnings, especially guidance on AI capital expenditure and the revenue generated from those investments. Investors will also watch the Federal Reserve’s policy decision, memory-chip pricing, Chinese capacity additions and whether selling spreads from chips into other sectors.
A rebound in semiconductors would require more than optimistic AI commentary. The market is increasingly asking for measurable returns, credible spending discipline and evidence that growing competition will not erode margins. Until those questions are answered, volatility in technology shares could remain much higher than in the broader market.
This article explains market developments and does not constitute investment advice.
Sources
Reuters: S&P 500 ends higher as investors await tech earnings
Reuters: Corning falls after weaker-than-expected sales forecast
Federal Reserve: FOMC meeting calendar
