Shares of Lam Research slid 7.9% in mid-day trading after a report indicated that a Shanghai-based, state-backed company has started mass production of domestically engineered immersion deep ultraviolet (DUV) lithography machines - a category of chipmaking equipment long dominated by Western suppliers. The report said those machines are expected to be delivered this year to major Chinese foundries and memory manufacturers, including Semiconductor Manufacturing International Corp, Hua Hong Semiconductor, and ChangXin Memory Technologies.
The market reaction was severe in part because China accounts for roughly 34-35% of Lam Research's total revenue, leaving the company particularly vulnerable if Chinese fabs shift more of their equipment sourcing to local suppliers. That concentration of revenue in a single market magnified investor sensitivity to the report and helped precipitate the sharp move in Lam's share price.
Lam’s drop came against a backdrop of vulnerabilities that had already been weighing on the stock. The company had seen a substantial run-up in the first half of 2026, leaving valuations stretched by some measures. Ongoing uncertainty around U.S. export controls for semiconductor equipment has also clouded the outlook. In addition, material insider selling - including a director’s sale of more than $19 million in shares - had left the shares susceptible to pronounced declines if negative news emerged.
The selloff spread across the semiconductor equipment sector, with ASML, Applied Materials and KLA Corp all retreating in sympathy with Lam Research. The broader chip complex was also pressured, with companies named in the report such as Micron, SanDisk and Marvell drawing selling alongside equipment vendors. By comparison, the Nasdaq Composite fell 0.4% and the S&P 500 edged down 0.1% on the day, underscoring Lam’s marked underperformance relative to major indices.
Investors were also facing near-term macro uncertainty, with a Federal Reserve policy decision scheduled later in the week adding another element of market jitteriness. Taken together, the China DUV report appears to have acted as the immediate catalyst for the sharp move, crystallizing existing concerns about Lam’s China revenue concentration and the potential long-term competitive challenge to Western semiconductor equipment suppliers.
Market participants will be watching closely as Lam Research prepares for its quarterly earnings call slated for July 29, which will now occur with heightened scrutiny following the report and the share-price reaction.
Clear summary
A report that a Shanghai-based, state-backed firm has begun mass-producing immersion DUV lithography machines and will deliver them to major Chinese chipmakers later this year sparked a 7.9% intraday drop in Lam Research shares, amplified by the company's substantial China revenue exposure, stretched valuations, U.S. export-control uncertainty, and recent insider selling. The move also pressured other equipment suppliers and chipmakers while broader markets saw modest declines.