SK Telecom
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SK Telecom Co., Ltd.
에스케이텔레콤 주식회사
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| Formerly | Korea Mobile Telecommunications (1984–1997)[1] | ||||||||||||
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| Type | Public company[2] | ||||||||||||
| Traded as | KRX: 017670 NYSE: SKM (American depositary shares)[2] | ||||||||||||
| Founded | 1984, as Korea Mobile Telecommunications[1] | ||||||||||||
| Headquarters | Jung-gu, Seoul, South Korea[1] | ||||||||||||
| Industry | Telecommunications[1] | ||||||||||||
| Services | Mobile network Fixed-line and internet Artificial-intelligence services[3] | ||||||||||||
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| Headquarters |
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| Official links |
| Homepage | Newsroom[1] |
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SK Group | ||||||||||||||||
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SK Telecom Co., Ltd. (에스케이텔레콤) is South Korea's largest mobile phone company. It is part of SK Group, the country's second-biggest business group, and it is the company that bought the chip maker SK hynix in 2012. In recent years it has recast itself as an artificial-intelligence (AI) company as well as a telecoms one.[1][3]
The company was founded in 1984 as Korea Mobile Telecommunications, a state-linked carrier. SK Group took it over in the mid-1990s, and in 1997 renamed it SK Telecom.[1][7] It has about 22 million mobile subscribers, roughly two-fifths of the market, ahead of its rivals KT and LG U+.[5]
In 2025 SK Telecom suffered one of the largest data breaches in Korean history, when the identifying keys inside millions of customers' SIM cards were stolen. The company replaced every affected SIM for free, was fined a record amount, and lost several hundred thousand subscribers.[8]
1 History✎
1.1 Korea Mobile Telecommunications (1984–1997)✎
The company was founded in 1984 as Korea Mobile Telecommunications, a state-linked carrier that ran car phones and paging services.[1] In 1996 it launched the world's first commercial mobile network built on CDMA, a digital standard that let far more callers share the same radio frequencies.[1]
SK Group — then called Sunkyong — took control of the carrier in the mid-1990s.[9] In 1997 the group brought its main businesses under a single brand, and the carrier took the name it still uses, SK Telecom.[7]
1.2 Growth under SK✎
In January 2002 SK Telecom bought the part of a smaller rival, Shinsegi Telecom, that it did not already own, and merged it in.[2] It rolled out faster networks in step with the rest of the industry — third-generation service in the 2000s and 4G LTE in 2011 — and in 2006 gathered its consumer products under a single brand, "T".[10]
In April 2019 SK Telecom took part in South Korea's launch of the world's first commercial 5G network.[11]
1.3 Hynix and the 2021 split✎
SK Telecom made the group's most important purchase in its history. In late 2011 it agreed to pay ₩3.4 trillion for a controlling stake of about 21% in the loss-making chip maker Hynix Semiconductor. Regulators approved the deal that December, and it closed in early 2012. The company was renamed SK hynix.[12][13]
Ten years later the two were separated. On 1 November 2021 SK Telecom split in two. The telecoms business kept the SK Telecom name, while its investments moved into a new listed company, SK Square. Those investments included the SK hynix shareholding, the 11st shopping site and the T Map navigation business.[14]
1.4 The AI pivot (2023–present)✎
From 2023 SK Telecom began describing itself as an AI company rather than only a phone company. Its main consumer product is A. (spoken "A dot"), a personal AI assistant that passed eight million users by the end of 2024.[15]
The strategy grew much larger in July 2026, when SK Group and NVIDIA announced a partnership worth more than US$500 billion. Under it, SK Telecom is to build and run a two-gigawatt AI facility in Korea using NVIDIA's systems and SK hynix memory, with the first phase due in 2027.[16]
2 Network and services✎
SK Telecom is the largest of South Korea's three mobile operators, with about 22.4 million subscribers and a market share of roughly 39% at the end of 2025, ahead of KT and LG U+.[5] About 17.5 million of its customers were on 5G.[3] Its fixed-line and home-internet business runs through SK Broadband, which became a wholly owned subsidiary in 2026.[6]
3 The 2025 data breach✎
In April 2025 SK Telecom discovered that hackers had planted malware in its systems and stolen data from customers' SIM cards. The stolen data included the secret keys that a SIM uses to prove its identity to the network. About 25 million people were affected — some 23 million SK Telecom subscribers and nearly two million more who used its network through smaller carriers.[8]
The company offered to replace every affected SIM card free of charge, at an estimated cost of ₩177 billion, and its chief executive said SK Telecom took full responsibility.[8] In August 2025 South Korea's Personal Information Protection Committee fined it ₩134.8 billion, the largest penalty ever issued under the country's privacy law. SK Telecom challenged the fine in court.[17]
The damage went beyond the fine. SK Telecom lost around 730,000 mobile subscribers over 2025 and, for the first time in a decade, its market share slipped below 40%.[5]
4 Finances✎
Figures are as reported by the company. One trillion won is roughly US$700 million.[3]
| Period | Revenue | Operating profit | Net income |
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| FY2024 | 17.94 | 1.82 | 1.44 |
| FY2025 | 17.10 | 1.07 | 0.38 |
Revenue and profit both fell in 2025. The company's operating profit dropped by about two-fifths and its net income by nearly three-quarters, mainly because of the cost of replacing SIM cards and the loss of customers after the data breach.[3][8]
5 See also✎
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- "History." SK Telecom (official). sktelecom.com. Retrieved July 2026.
- SK Telecom Co., Ltd., Form 20-F, filed with the U.S. Securities and Exchange Commission. sec.gov. Retrieved July 2026.
- "SK Telecom Announces 2025 Annual Results." SK Telecom Newsroom (official). news.sktelecom.com. Retrieved July 2026.
- "SK Telecom names Jung Jae-heon as chief executive." KED Global, 2026. biggo.com. Retrieved July 2026.
- "SK Telecom loses subscribers after data breach." UPI, January 12, 2026. upi.com. Retrieved July 2026.
- SK Telecom Co., Ltd., Form 6-K, filed with the U.S. Securities and Exchange Commission, 2026. sec.gov filing. Retrieved July 2026.
- "Inside SK: History of the SK Brand and the Wings of Happiness." SK Group (official). eng.sk.com. Retrieved July 2026.
- "SKT takes full responsibility amid USIM hacking fallout." Light Reading, 2025. lightreading.com. Retrieved July 2026.
- "SK Group digitizes former chairman's archive." The Korea Times, April 2, 2025. koreatimes.co.kr. Retrieved July 2026.
- "SK Telecom Launches New Corporate Brand 'T'." SK Telecom (official), August 2006. sktelecom.com. Retrieved July 2026.
- "South Korea launches 5G wireless network." ABC News, April 2019. abcnews.go.com. Retrieved July 2026.
- "SK Telecom to Acquire 21% Stake in Hynix Semiconductor for $3.05 Billion." Bloomberg, November 14, 2011. bloomberg.com. Retrieved July 2026.
- "Regulator OKs SK Telecom's Hynix purchase." The Korea Times, December 27, 2011. koreatimes.co.kr. Retrieved July 2026.
- "SK Telecom Completes Company Split." SK Telecom (official press release), November 2021. sktelecom.com. Retrieved July 2026.
- "'A.' surpasses 8 million users." SK Telecom Newsroom (official). news.sktelecom.com. Retrieved July 2026.
- "SK Group and NVIDIA Expand Strategic Partnership Across AI Factories and Next-Generation Memory." NVIDIA Newsroom (official), July 2026. nvidianews.nvidia.com. Retrieved July 2026.
- "Privacy watchdog hits SKT with record $97M fine over data breach." Light Reading, August 2025. lightreading.com. Retrieved July 2026.