Key Highlights

  • Sandisk (NASDAQ:SNDK) lost 22.26% on November 5, 2026, the steepest drop among S&P 500 members, while Western Digital fell 17.35% and Seagate shed more than 16%.
  • Lam Research (NASDAQ:LRCX) finished down 16.36%, after which its board approved a USD 25 billion repurchase plan and a USD 0.33 quarterly payout.
  • A 16.43% slide left Marvell Technology (NASDAQ:MRVL) at USD 133.55, roughly 22% below its November 2 close of USD 171.41 (own arithmetic on two published prices).
  • Lumentum (NASDAQ:LITE) is reported down 18.68% in a single market wrap, an unconfirmed figure, and it is also the target of a reported all-stock offer from Marvell.

Sandisk (NASDAQ:SNDK): Steepest Drop Among S&P 500 Members

Sandisk (NASDAQ:SNDK) slid 22.26% on Thursday, November 5, 2026, the largest decline in the S&P 500 that day. Western Digital (NASDAQ:WDC) lost 17.35% in the same session. Seagate (NASDAQ:STX) gave up more than 16%. Sandisk produces flash storage for phones, computers and data centers, whereas Western Digital and Seagate concentrate on hard drives. Commentary in the market wraps blamed fears that Democratic victories in Congress, Texas and Georgia might curb data-center building, plus weak Qualcomm guidance that pointed to a memory-component squeeze. Because flash Demand depends on AI data-center expansion, even a whiff of slowdown can quickly reset what investors expect. No company-specific announcement for Sandisk (NASDAQ:SNDK) appeared in the reviewed material, which makes the move look sector-driven. The Nasdaq Composite lost 5.52% and the S&P 500 dropped 4.36%. One wrap said Micron and AMD were each down about 17% and Nvidia about 9%, a claim a second source failed to corroborate. Memory and storage pricing moves in cycles, and a plunge beyond 20% is rare for an S&P 500 name. Market commentary framed the drop as a sign of how crowded the AI hardware trade had grown, though no verified positioning data backs that. Friday futures were mixed.

Lam Research (NASDAQ:LRCX): Authorization Arrives After a Plunge

Thursday's broad chip rout pushed Lam Research (NASDAQ:LRCX) down 16.36%, a session in which the Nasdaq-100 lost 6.36% and semiconductor shares fell across the board. Later that day, the company announced that its board had cleared a fresh USD 25 billion share repurchase authorization, one that sits on top of an earlier program whose remaining balance the release did not disclose. Indicative market data showed the shares up about 6.26% in after-hours trading, a move that can easily reverse. A repurchase authorization is permission rather than a promise: Buybacks can run on the open market or through private deals, carry no end date and can be halted at any time. Lam Research (NASDAQ:LRCX) manufactures the equipment chipmakers use to fabricate devices, so its orders track their spending plans. A USD 0.33 quarterly Dividend also received board approval, with payment due January 6, 2027 for shareholders of record as of December 2, 2026. The release included no new guidance, so the repurchase is a Capital allocation decision rather than a change in outlook. Retiring shares lifts per-share Earnings once executed, yet the cash used could otherwise fund research or added capacity. The partial after-hours recovery leaves most of the 16.36% loss in place.

Marvell Technology (NASDAQ:MRVL): Lumentum Deal Pressures the Stock Further

Marvell Technology (NASDAQ:MRVL) dropped 16.43% on Thursday, finishing at USD 133.55. That slide came after a Lumentum transaction unveiled on November 2, 2026, when Marvell shares had already dropped 12.7% to USD 171.41. Published reports also cited declines of 13.2% on October 29 and 10.0% on October 30, tied to reports that a deal was close. The company designs chips for data infrastructure, covering networking, storage and AI data centers. Per one published account, the all-stock proposal would swap 4.5 Marvell shares for each Lumentum share, carry an implied Enterprise value near USD 115 billion and leave Marvell holders with about 67% ownership; that account has not been checked against a filing. Valued at Thursday's closing price, the fixed ratio gives each Lumentum share a value of roughly USD 601 (calculated, adjustments ignored). A separate report hinted at Shareholder objections, which has not been confirmed. Based on the material reviewed, Marvell Technology (NASDAQ:MRVL) has not altered the terms. Because the ratio is locked, Marvell issues the same number of shares regardless of its price, so a cheaper stock reduces what the transaction is worth while the ownership split holds steady. A formal Merger filing would be the key document to watch, since it should describe the funding, the conditions for closing, the timing of votes and any breakup payments; none of those details surfaced in the reviewed material.

Lumentum (NASDAQ:LITE): Shares Track Marvell and Fall With AI Names

Lumentum (NASDAQ:LITE) is reported to have fallen 18.68% on Thursday. A reported 19.62% decline also hit Astera Labs (NASDAQ:ALAB). Those figures are single-source, drawn from one market wrap, and remain unconfirmed, with no closing prices located for either name. Lumentum makes lasers and optical parts for Data Center networks, and Astera Labs supplies connectivity chips that shuttle data between processors and memory. With Marvell's exchange ratio locked in, Lumentum (NASDAQ:LITE) generally trades in step with Marvell's share price, which dropped 16.43% that same session. One account, and only one, described a steep drop the week before. A reported decision by Microsoft not to widen one capacity agreement with a cloud provider added to the unease, though the company has not confirmed it. No cause specific to either company was located. Lumentum (NASDAQ:LITE) confronts approval and integration hurdles, and holders are exposed to both its own stock and Marvell's. The October jobs report is due Friday morning, and single-day drops near 19% can either extend or reverse. The NASDAQ listing shown for Astera Labs has not been verified against a filing.

Where Things Stand

The thread running through all four is a sector-wide retreat in AI hardware, prompted by data-center worries rather than by one company's news. Sandisk (NASDAQ:SNDK) gave up 22.26% with nothing company-specific to account for it. Lam Research (NASDAQ:LRCX) answered the sell-off with a USD 25 billion repurchase plan, although that plan is discretionary and has no fixed end. Marvell Technology (NASDAQ:MRVL) took the market decline on top of questions around a very large share-based acquisition. Lumentum (NASDAQ:LITE) also feels the effect of the fixed exchange ratio, and its figure rests on a single report. Upcoming markers include the jobs report, Friday's session, any merger filing and further data-center policy headlines, along with whether chip peers stabilize after Thursday's double-digit declines. Nothing here is a prediction.