Micron, SanDisk, AMD and Qualcomm stocks plunge as US stock market crashes today: Dow, Nasdaq and S&P 500 turn red as chip selloff deepens – What is driving Wall Street's sudden reversal?

Why is the US stock market down today, November 5, 2026? Wall Street's post-election rally lasted barely a day for some of the biggest semiconductor stocks. On Wednesday, November 4, the Dow Jones, S&P 500 and Nasdaq posted strong gains after Democrats secured a decisive midterm election victory. But the optimism has given way to another sharp selloff in technology shares on Thursday.

This time, even the Dow has turned lower. Investors are selling AI hardware stocks as concerns grow over the future of US data center construction, borrowing costs and weaker demand for smartphone chips. Micron, SanDisk, Western Digital and Seagate are extending their losses, while AMD, Nvidia and Qualcomm are also facing heavy selling.

US stock market today: Dow falls 0.9%, S&P 500 drops 2% and Nasdaq plunges 3.6%

The three major US stock indexes reversed their post-election gains on Thursday. By 10:10 a.m. ET, the Dow Jones Industrial Average was down 502 points, or 0.9%. The S&P 500 had fallen 2%, while the Nasdaq Composite was down 3.6%, according to Associated Press market data.


The selloff was concentrated in technology and AI-related companies. Nvidia shares fell 6.3%, while Advanced Micro Devices (AMD) plunged 13.1%. Qualcomm also dropped more than 9% in early trading.

The reversal came after Wednesday's rally, when the Dow gained around 3%, or 1,569 points, the S&P 500 advanced 1.58% and the Nasdaq rose 1.44%. Investors initially welcomed the reduced uncertainty over the composition of Congress.

Micron stock price (MU): Shares fall again as Taiwan plant delay adds to concerns

Micron Technology (NASDAQ: MU) shares fell 7% on Wednesday, closing at $795.23. The stock faced another decline in Thursday's premarket trading, falling around 4.7% in an early market snapshot.

Investors are questioning whether the expansion of US data centers will continue at its current pace. Micron's memory products, including DRAM and high-bandwidth memory, are important components in AI servers. Any delay in infrastructure spending could affect future demand expectations.

There is also a company-specific development. Bloomberg reported on Thursday that Micron had suspended plans for a $4.5 billion memory-chip plant in Taiwan because of a prolonged labour dispute. Reuters said it could not independently verify the report. Micron had not immediately responded to its request for comment.

SanDisk stock (SNDK) slides further as memory chip selloff deepens

SanDisk (NASDAQ: SNDK) was among the weakest performers in the memory and storage sector. Its shares dropped 7.9% on Wednesday and fell another 6.5% in Thursday's premarket trading.

The company is exposed to changes in storage demand across enterprise and data center markets. Investors are concerned that restrictions on new data center construction could affect future spending on storage infrastructure.

Western Digital stock (WDC) and Seagate stock (STX) extend losses

Western Digital (NASDAQ: WDC) shares declined 6.7% on Wednesday and fell around 5% in Thursday's premarket session.

Seagate Technology (NASDAQ: STX) performed even worse in the previous session, losing 8.1%. Its shares dropped another 5.4% in early Thursday premarket trading.

Both companies are linked to the storage infrastructure required by large data centers.

Qualcomm stock (QCOM) falls over 9% as smartphone chip sales disappoint

Qualcomm's earnings added another reason for investors to sell semiconductor stocks. The company reported fiscal fourth-quarter revenue of $10.322 billion, down 8.4% from a year earlier. Full-year fiscal 2026 revenue declined 2.6% to $43.12 billion, although net profit increased 146% to $13.628 billion.

Qualcomm's handset chip revenue fell 26% to $5.14 billion, missing Wall Street estimates. Its adjusted earnings-per-share forecast midpoint for fiscal 2027's first quarter was $2.25, below analyst expectations.

Qualcomm shares dropped more than 9% in early Thursday trading.

Why are chip stocks falling while the US stock market reverses its election rally?

Democratic victories have increased the possibility of stricter scrutiny of data center construction, particularly in states where opposition to new projects has grown.

An NBC and SSRS exit poll found that around 76% of voters opposed new data centers being built in their communities. Investors are assessing whether local restrictions could delay projects that technology companies had expected to support AI growth.

Borrowing costs are another concern. Building AI infrastructure requires substantial capital, and higher financing costs can make new projects more expensive.