Mitsui Chemicals to buy JSR for $8.2bn as Japan rebuilds its chip materials base

Chipmakers buy photoresists from a shrinking pool of Japanese suppliers. A change of owner at JSR shifts who controls that capacity. The price is larger than Mitsui Chemicals' entire market value. That means the buyer is taking on real balance-sheet risk to get into chip materials. Neither company has announced the deal.

Mitsui Chemicals moves for JSR

If it goes through, the deal would be the largest-ever acquisition in Japan's chemicals sector.

JSR started in 1957 as Japan Synthetic Rubber Co. It has become a leading producer of photoresists, the material that transfers circuit patterns onto semiconductor wafers. JIC bought the company almost two years ago for 900 billion yen, roughly $5.9 billion, to consolidate Japan's semiconductor materials sector. Mitsui Chemicals is also looking to expand its own chip materials business, Electronics For You reported.

What the price says

Mitsui Chemicals is worth 800 billion yen ($5.05 billion) on the market. The buyer would commit more than its own market capitalisation to move into chip materials. Electronics For You reported that JIC is selling to take advantage of higher valuations for chipmaking firms and to direct money into Japan's AI sector.

Materials, not fabs

The push is broader than one deal. SoftBank entered a joint research partnership with AGC, Toppan Holdings, Aisin, Asahi Kasei and DIC on a quantum-computing platform for materials development. NEDO selected the project for funding. It runs from fiscal 2026, which ends on 31 March 2027, through fiscal 2028.

SoftBank's job is to link quantum computers and supercomputers. Targets include next-generation battery materials, optical materials for displays and sensors, and superconducting materials. SoftBank said limits on qubit scalability and error correction stop quantum computers from carrying out large-scale calculations on their own. That is why the project pairs them with AI methods.

The inputs above the chemicals

Above the chemicals sit the raw inputs. Japan relies on China for about 90 percent of its rare earths.

In February 2026 Japan became the first country to continuously retrieve rare-earth mud from a depth of 6,000 metres off Minamitorishima, its easternmost island. The island lies about 1,200 miles southeast of Tokyo. The International Seabed Authority counts more than 30 signed exploration contracts for seabed in international waters.

That programme has drawn scepticism. Shigeru Tanaka, director of the Asia-Pacific Resource Center, told The Diplomat that a moratorium until 2030 "shouldn't really be a big deal for Japan". He also said deep-sea mining, as things stand, is economically unfeasible. Japan has resisted pressure to hold off on commercial extraction until at least 2030.

The Diplomat's articles disagree on one detail. One dates the Chinese export halt to 2010, the other to 2012.

What happens next

The JSR sale is expected to be announced this month. No closing date or approval timetable has been published for the transaction.