South Korea’s only maker of semiconductor silicon wafers is moving from SK Group to Doosan Group. SK Corp said on Thursday its board approved a share purchase agreement to transfer 47,322,350 common shares of SK Siltron to Doosan Corp. The disposal amount is 2.3 trillion won, equivalent to 2.68% of SK Corp’s equity capital. The stake equals 70.6%. The expected closing date is Jan. 31, 2027.

SK Corp said the share transfer is aimed at strengthening financial soundness and securing funds to ensure future growth engines. The disposal includes 34,181,910 shares currently held and 13,140,440 shares to be acquired by exercising a call option under a total return swap (TRS), a derivatives transaction in which profit and loss from shares are exchanged with the counterparty. The disposal amount will be finally fixed after an adjustment process.

SK Corp will also receive an excess profit-sharing portion in addition to the sale proceeds. If SK Siltron exceeds annual targets from 2027 to 2034, SK Corp will receive an amount calculated by applying its stake ratio to 40% of the excess. The benchmark is earnings before interest, taxes, depreciation and amortisation (EBITDA), and the target rises from 890 billion won in 2027 to 1.7 trillion won in 2034. If quality certification is completed for 4 items for specific clients by the end of June 2029, 25 billion won per item will also be subject to settlement.

The contract was signed about 7 months after Doosan was selected as the preferred bidder at the end of last year. The deal will close only after conditions precedent are met, including approvals from relevant authorities.

Founded in 1983, SK Siltron is the only company in South Korea that produces semiconductor silicon wafers. Last year, revenue was about 2 trillion won and operating profit exceeded 400 billion won. Its main products are 300 mm and 200 mm wafers, and the 300 mm wafer is assessed as having competitiveness around third place in the global market. Wafers are a material that forms the basis of semiconductor chips, and their quality determines production yield and performance. The area has high entry barriers because it requires large-scale investment and long-term accumulation of technology.

The silicon wafer market is shared by 5 companies — SK Siltron, Japan’s Shin-Etsu Chemical and SUMCO, Taiwan’s GlobalWafers and Germany’s Siltronic — which together hold more than 90%. This means Doosan has secured the wafer business, a key material in front-end processes, following Doosan Tesna, which handles semiconductor testing. Together with Doosan Corp’s Electronics BG, which deals in electronic materials, the scale of the group’s semiconductor and advanced materials business also expands.