Mitsui Chemicals, a Tokyo-based chemical producer, said Nov. 9 it agreed to acquire JSR Corp., a Japanese supplier of semiconductor materials, in a transaction valued at approximately ¥1.84 trillion ($11.6 billion), including assumed debt and other liabilities. The acquisition is intended to expand Mitsui's electronic materials business and accelerate a broader shift toward specialty chemicals.

Under the agreement, Mitsui will acquire all JSR common shares held by an investment fund managed by JIC Capital, an affiliate of government-backed Japan Investment Corp. The Development Bank of Japan will also participate in the transaction. Following completion, Mitsui is expected to hold all voting rights in JSR, which will become a consolidated subsidiary.

The transaction, which Reuters described as the largest acquisition in Japan's chemical sector, is expected to close in the second half of fiscal 2027, subject to regulatory approvals.

JSR's electronic materials portfolio includes photoresists used in semiconductor lithography, chemical mechanical planarization (CMP) slurries, multilayer materials and precursors for atomic layer deposition (ALD) and chemical vapor deposition (CVD). These products serve front-end wafer fabrication processes, including lithography, cleaning and deposition, as well as back-end manufacturing and advanced packaging.

Mitsui already supplies semiconductor and optical materials, including photomask pellicles, process tapes and specialty optical resins. The companies said combining their technologies, product portfolios, customer relationships and global operations will expand product development and supply capabilities across the semiconductor industry.

JSR operates manufacturing facilities in Japan, the United States, Europe, China, South Korea and Taiwan, with research and development centers in Japan. Mitsui's presentation identifies opportunities to expand semiconductor materials offerings across front-end processing, back-end manufacturing, packaging and assembly.

The acquisition is part of a broader portfolio restructuring intended to shift Mitsui toward higher-growth specialty chemicals businesses. The company is also planning to separate its Basic & Green Materials business, including functional polymers, into an integrated business entity in fiscal 2027. In addition, Mitsui has identified JSR's Life Sciences business for divestiture and plans to review other businesses and affiliates as part of its portfolio rationalization.

Why it Matters

Semiconductor manufacturing relies on specialized chemical materials at multiple stages of production. Photoresists enable pattern formation during lithography, CMP slurries are used to planarize wafer surfaces between processing steps, and ALD/CVD precursors supply materials for depositing thin films. These materials are important to advanced chip manufacturing and packaging processes.

Combining JSR's portfolio with Mitsui's existing semiconductor materials business would give the company a broader presence across these manufacturing stages. The companies have identified expanded research, product development and global supply capabilities as priorities following the acquisition.

The transaction has not yet resulted in announced changes to individual manufacturing sites, production capacity or product transfers. Both companies must complete the regulatory approval process before the acquisition can close.