SK Inc. is the holding company of SK Group, South Korea’s second-largest conglomerate. Headquartered in Seoul and listed on the Korea Exchange (ticker 034730), it sits at the top of a portfolio spanning semiconductors, energy and petrochemicals, telecommunications, advanced materials, and life sciences.
Unlike a purely passive holding company, SK Inc. combines three roles: it manages and allocates capital across the group’s affiliates, it operates an in-house advanced materials business supplying specialty gases to the semiconductor industry, and it makes direct strategic investments in future growth areas — notably hydrogen, next-generation nuclear power, batteries, and biopharmaceuticals. The company is chaired by Chey Tae-won, whose family controls the group, and group-wide strategy is coordinated through the SUPEX Council, a consultative body of the group’s top executives.
Company History
SK Inc. in its current form is a relatively recent construct, although the group it controls dates back to 1953, when Chey Jong-gun founded Sunkyong Textiles from the ruins of a war-damaged mill. The group subsequently integrated into fibers, petrochemicals, and energy, most notably through the 1980 acquisition of state refiner Yukong, and later into telecommunications in the 1990s, adopting the SK name in 1998.
The corporate lineage of the holding company itself runs through two entities. SK C&C was founded in 1991 as the group’s IT services arm and became the vehicle through which Chairman Chey Tae-won held much of his group interest. Separately, in 2007 the group’s listed flagship SK Corporation reorganized into a holding structure, creating SK Holdings above the operating businesses. On August 1, 2015, SK C&C and SK Holdings merged — a transaction that simplified the group’s complex cross-shareholding arrangements and consolidated the chairman’s control under a single listed holding company, which retained the SK Holdings name.
In January 2021 the company was renamed SK Inc., a rebranding intended to signal its evolution from a passive holding company into an active “investment-specialized company” focused on four growth pillars: advanced materials, green energy, bio, and digital. Later that year, in December 2021, it absorbed group affiliate SK Materials, giving the holding company its own operating division producing semiconductor specialty gases. More recently, SK Inc. has driven a major portfolio restructuring, including the 2024 merger of SK Innovation and SK E&S to consolidate the group’s energy businesses, which raised SK Inc.'s stake in the combined entity to a majority position.
Activities
SK Inc.'s activities fall into three broad categories:
- First, its holding company function: portfolio strategy, capital allocation, governance oversight, and brand management across a group with combined assets among the largest in Korea.
- Second, direct investment in future growth engines. Flagship examples include a roughly US$1.6 billion investment in US hydrogen fuel cell company Plug Power in 2021 (followed by a Korean joint venture), an investment in TerraPower, the US small modular reactor developer founded by Bill Gates, backing for Monolith’s clean hydrogen and carbon black technology, and participation in silicon anode developer Group14 Technologies.
- Third, its operating businesses. The materials division inherited from SK Materials is a world leader in specialty gases for semiconductor and display manufacturing, including nitrogen trifluoride (NF3), tungsten hexafluoride, and silane, alongside precursors and on-site industrial gas supply. In life sciences, SK Inc. wholly owns SK Pharmteco, a contract development and manufacturing organization assembled through acquisitions in the US and Ireland, and is the controlling shareholder of SK Biopharmaceuticals, developer of the epilepsy treatment cenobamate (Xcopri).
Subsidiaries
SK Inc. is the largest shareholder of SK Innovation, the group’s energy and chemicals arm encompassing refining (the Ulsan complex, one of the world’s largest), petrochemicals, lubricants, LNG, and the EV battery producer SK On.
Following the 2024 merger with SK E&S, SK Inc. holds:
- a majority stake of roughly 55 percent. It holds around 30 percent of SK Telecom, Korea’s largest mobile carrier
- a similar stake in SK Square, the technology investment company spun off from SK Telecom in 2021 — through which SK Inc. indirectly controls SK Hynix, the world’s second-largest memory chipmaker and leading supplier of high-bandwidth memory for AI applications.
Other major holdings include:
- SKC (around 40 percent), a producer of chemical and advanced materials for semiconductors, displays, and batteries
- SK Networks (around 40 percent), the group’s trading and services affiliate
- SK Siltron (roughly 70 percent), a manufacturer of semiconductor silicon wafers including silicon carbide wafers
- SK Biopharmaceuticals (roughly two-thirds)
- wholly owned SK Pharmteco.
The materials division also encompasses several joint ventures, including precursor maker SK Trichem and industrial gas supplier SK Materials Airplus.
