As Korea’s first wireless telecommunications service provider, we have a recognized history of leadership and innovation in the domestic telecommunications sector. Today, we remain Korea’s leading wireless telecommunications services provider and have continued to pioneer the commercial development and implementation of state-of-the-art wireless technologies. We had 23.5 million mobile phone subscribers, including MVNO subscribers leasing our networks, as of December 31, 2025, representing a market share of 41.6%, the largest market share among Korean wireless telecommunications service providers. We believe that we are also a leader in developing new products and services that reflect the increasing convergence of telecommunications technologies, as well as the growing synergies between the telecommunications sector and other industries. In February 2012, we acquired an equity stake in SK Hynix, one of the world’s largest memory-chip makers by revenue, for an aggregate purchase price of Won 3.4 trillion, and became its largest shareholder. In November 2021, we transferred all of our 20.1% equity interest in SK Hynix to SK Square pursuant to the Spin-off, as further described below. Effective as of November 1, 2021, we conducted the Spin-off, pursuant to which we spun off our equity interests in certain subsidiaries and investees (collectively comprising the Spin-off Portfolio Companies) engaged in the semiconductor and certain other non-telecommunications businesses, including our security, e-commerce and other new ICT businesses (collectively comprising the Spin-off Businesses) to SK Square, a newly established holding company, and we distributed SK Square’s shares of common stock on a pro rata basis to the holders of our common stock. In connection with the Spin-off, we also engaged in a 5-to-1 stock split of our common stock (the “Stock Split”), pursuant to which the par value of our common stock changed from Won 500 per share to Won 100 per share and the number of issued shares of our common stock increased from 72,060,143 shares to 360,300,715 shares, in each case effective as of October 28, 2021. Immediately following, and as a result of, the Stock Split, each ADS outstanding as of October 28, 2021 represented five-ninths of one share of our common stock. On March 31, 2026, we had a market capitalization of approximately Won 16.4 trillion (US$10.7 billion) or approximately 0.4% of the total market capitalization on the KRX KOSPI Market, making us the 48th largest company listed on the KRX KOSPI Market based on market capitalization on that date. Our ADSs, each representing five-ninths of one share of our common stock, have traded on the NYSE since June 27, 1996. We are a corporation with limited liability organized under the laws of Korea. We established our telecommunications business in March 1984 under the name Korea Mobile Telecommunications Co., Ltd. We changed our name to SK Telecom Co., Ltd., effective March 21, 1997. In January 2002, we merged with Shinsegi Telecom Co., Ltd. (“Shinsegi”), which was then the third-largest wireless telecommunications service provider in Korea. Our registered office is at SK T-Tower, 65, Eulji-ro, Jung-gu, Seoul 04539, Korea and our telephone number is +82-2-6100-1532. Our website address is www.sktelecom.com. The SEC maintains a website (www.sec.gov), which contains reports, proxy and information statements and other information regarding issuers that file electronically with the SEC. Korean Telecommunications Industry Established in March 1984, we became the first wireless telecommunications service provider in Korea. We remained the sole provider of wireless telecommunications services until April 1996, when Shinsegi commenced cellular service. The Government began to introduce competition into the fixed-line and wireless telecommunications services markets in the early 1990’s. During this period, the Government allowed new competitors to enter the fixed-line sector, sold a controlling stake in us to the SK Group, and granted a cellular 24 Table of Contents license to our first competitor, Shinsegi. In October 1997, three additional companies began providing wireless telecommunications services under Government licenses to provide wireless telecommunications services. In 2000 and 2001, the Korean wireless telecommunications market experienced significant consolidation. In January 2002, Shinsegi was merged into us. Additionally, two of the other wireless telecommunications services providers merged. There are currently three mobile network operators in Korea: us, KT and LG U+. As of December 31, 2025, the market share of the Korean wireless telecommunications market, in terms of number of mobile phone subscribers, of KT and LG U+ was approximately 30.8% and 27.6%, respectively (compared to our market share of 41.6%), each including MVNO subscribers leasing the respective networks. As of December 31, 2025, MVNOs had a combined market share of 18.3%, of which MVNOs leasing our networks represented 3.1%, MVNOs leasing KT’s networks represented 7.0% and MVNOs leasing LG U+’s networks represented 8.1%. In January 2024, the Government allocated 800 MHz of bandwidth in the 28 GHz spectrum to Stage X to provide nationwide wireless network services. However, in July 2024, the Government revoked such allocation citing Stage X’s failure to meet the paid-in capital requirement and discrepancies in the actual ownership ratios of major shareholders and ownership structure compared to the information included in its frequency allocation application. Telecommunications industry growth in Korea has been among the most rapid in the world, with fixed-line penetration being under five lines per 100 population in 1978 and increasing to 47.9 lines per 100 population as of December 31, 2006 before decreasing to 19.0 lines per 100 population as of December 31, 2025, and mobile phone penetration reaching 110.6 subscribers per 100 population as of December 31, 2025. The table below sets forth certain subscription and penetration information regarding the Korean telecommunications industry as of the dates indicated: As of December 31, 2025 2024 2023 (In thousands, except for per population amounts) Population of Korea(1) 51,117 51,217 51,325 Mobile Phone Subscribers 56,531 (2) 56,185 (2) 56,164 Mobile Phone Subscribers per 100 Population 110.6 109.7 109.4 Telephone Lines in Service 9,692 10,325 10,974 Telephone Lines per 100 Population 19.0 20.2 21.4 (1) Source: The Ministry of the Interior and Safety. (2) Excludes internal carrier lines and inbound roaming lines pursuant to a change in the presentation of the MSIT’s published data in 2024. As of December 31, 2024 and December 31, 2025, an aggregate of 693 thousand and 927 thousand internal carrier lines and inbound roaming lines, respectively, were in existence. Since the introduction of short text messaging in 1998, Korea’s wireless data market has grown rapidly. This growth has been driven, in part, by the rapid development of wireless Internet service since its introduction in 1999 and the implementation of LTE and 5G technologies providing for fast data transmission speeds and large data transmission capacity. The table below sets forth certain penetration information regarding the number of smartphones that have direct access to the Internet using mobile Internet technology and mobile phone subscribers in Korea as of the dates indicated: As of December 31, 2025 2024 2023 (In thousands, except for percentage data) Number of Smartphones 56,875 56,112 55,126 Total Number of Mobile Phone Subscribers 56,531 (1) 56,185 (1) 56,164 Penetration of Smartphones 100.6 % 99.9 % 98.2 % 25 Table of Contents (1) Excludes internal carrier lines and inbound roaming lines pursuant to a change in the presentation of the MSIT’s published data in 2024. As of December 31, 2024 and December 31, 2025, an aggregate of 693 thousand and 927 thousand internal carrier lines and inbound roaming lines, respectively, were in existence. In addition to its well-developed wireless telecommunications sector, Korea has one of the largest Internet markets in the Asia Pacific region. From the end of 2010 to the end of 2025, the number of broadband Internet access subscribers increased from approximately 17.2 million to approximately 25.2 million. In connection with such growth in broadband Internet usage, the number of IPTV subscribers has also increased rapidly. The table below sets forth certain information regarding broadband Internet access subscribers and IPTV subscribers as of the dates indicated: As of December 31, 2025 2024 2023 (In thousands) Number of Broadband Internet Access Subscribers(1) 25,234 24,722 24,098 Number of IPTV Subscribers 21,994 21,828 21,582 (1) Includes subscribers accessing Internet service using digital subscriber line, or xDSL, connections; cable modem connections; local area network, or LAN, connections; fiber-to-the-home, or FTTH, connections and satellite connections. Item 4.B. Business Overview Overview We are Korea’s leading wireless telecommunications services provider, and our core business is centered on providing wireless and fixed-line telecommunications services. We maintain the largest market share in the Korean market for wireless telecommunications services. Our revenue is primarily generated from our cellular services segment, which accounts for a substantial portion of our consolidated revenue, with additional contributions from our fixed-line telecommunications services and other business segments. We continue to develop, enhance and operate our telecommunications services through ongoing investments in network infrastructure and the adoption of advanced technologies, with a focus on improving service quality, reliability and operational efficiency. In addition to our core telecommunications services, we offer a broad range of complementary services and solutions that leverage our telecommunications platforms and digital infrastructure capabilities. These include IoT solutions and enterprise communications services, cloud services, subscription services, advertising and curated shopping services, AI business-to-consumer (“B2C”) services and AI business-to-business (“B2B”) services. We seek to drive growth by enhancing our core telecommunications services while selectively expanding complementary services that leverage our network infrastructure and customer base. These services are designed to enhance customer engagement, expand our service offerings and support the overall competitiveness of our core telecommunications business. Our operations are reported in three segments: • cellular services, which include wireless voice and data transmission services, sales of wireless devices, cellular interconnection services, as well as IoT solutions and enterprise communications services, cloud services, subscription services, advertising and curated shopping services, AI B2C services and AI B2B services; • fixed-line telecommunications services, which include fixed-line telephone services, broadband Internet services, advanced media platform services (including IPTV and cable TV services), and business communications and related infrastructure services; and • other businesses, which include our T-commerce business and certain other miscellaneous businesses. 26 Table of Contents Our Business Strategy We operate in an environment characterized by rapid technological advancements, evolving customer needs and increasing convergence across industries. In response to these trends, we focus on strengthening our core telecommunications business and enhancing customer trust and value, while selectively expanding our AI-related capabilities to support our long-term growth. Our strategy is centered on maintaining our leadership in the Korean market for wireless telecommunications services, improving service quality and operational efficiency, and pursuing disciplined growth opportunities in selected areas, including AI-related initiatives that complement our existing business. In doing so, we seek to leverage our core telecommunications infrastructure and subscriber base to support the expansion of complementary services and improve operational efficiency. Our principal business strategies are as follows: • Strengthening our core telecommunications business. We seek to maintain our leadership in the Korean market for wireless telecommunications services by enhancing network quality, expanding service offerings and improving customer experience. We are focused on optimizing our network operations and improving service reliability, including through the adoption of advanced technologies such as AI-based network management and automation. We also continue to leverage data analytics to better understand customer needs and to provide more relevant and personalized products and services. • Enhancing customer trust and service stability. We place significant emphasis on strengthening customer trust and delivering stable and reliable services. Following recent cybersecurity incidents that have affected the telecommunications industry, we have taken steps to enhance our security systems and internal control processes, including upgrades to our security infrastructure and improvements in asset management and monitoring capabilities. We plan to continue to invest in technologies and processes designed to enhance the security, reliability and resilience of our services, and to reinforce our ability to respond to evolving risks, with the aim of maintaining and improving customer trust. • Selectively expanding AI-related capabilities. We are pursuing a disciplined and selective approach to the development of our AI-related capabilities by focusing on areas where we can enhance our existing services, improve operational efficiency or develop solutions with clear commercial applications. We are investing in selected AI infrastructure and computing capabilities, as well as AI-based solutions that can be integrated into our telecommunications services or offered to enterprise customers. We aim to leverage our existing assets, including our network infrastructure and customer base, to support the development of these capabilities. • Improving operational efficiency and pursuing sustainable growth. We are focused on improving operational efficiency across our business and optimizing our cost structure, including through automation and data-driven decision-making. In addition, we continue to pursue long-term sustainable growth by enhancing the efficiency of our operations, including our network infrastructure, and by supporting the responsible use of technology. Through these efforts, we aim to create long-term value for our shareholders and other stakeholders. In line with our business strategies as discussed above, we are striving to enhance our operational efficiency through our efforts to reduce operating expenses, optimize capital expenditures and reorganize non-essential business lines and investments. For example, in order to streamline our operating expenses, we have been actively utilizing AI technology in various operational processes, including our marketing activities and customer services. Furthermore, we have shifted the focus of our 5G network-related capital expenditure from expanding network coverage and increasing maximum data transmission speed to enhancing network quality. Moreover, in December 2024, we entered into agreements with Samgu Inc. and its affiliates to dispose of a 70% equity interest in SK M&Service, as well as our 100% equity interest in our former wholly-owned subsidiary NATE Communications Corporation, which operates the “Nate” internet portal, and the entirety of our 50% equity interest in our former associate F&U Credit Information, which provides credit information services. The disposals of NATE Communications Corporation, SK M&Service and F&U Credit Information were completed in January 2025, February 2025 and April 2025, respectively. In April 2025, we disposed of 10,818,510 shares of 27 Table of Contents Kakao Corp. (representing a 2.4% interest), which we had previously acquired in 2019 as part of a strategic partnership between the two companies, for Won 413.3 billion. More recently, in December 2025, we entered into an agreement to sell our entire equity stake in SK Stoa, which operates our T-commerce business, and Media S, which operates two TV channels and co-produces original television entertainment contents, to Rapport Labs Inc., a Korea-based e-commerce company, as part of our ongoing strategy to streamline and optimize our overall business portfolio. Such transaction is currently pending subject to regulatory approval and other customary closing conditions. Cellular Services We offer wireless voice and data transmission services, sell wireless devices and provide various other technological solutions and services through our cellular services segment. Our wireless voice and data transmission services are offered through our backbone networks that collectively can be accessed by substantially all of the Korean population. We had 23.5 million mobile phone subscribers, including MVNO subscribers leasing our networks, as of December 31, 2025, representing a market share of 41.6%, the largest market share among Korean wireless telecommunications service providers. We launched our wireless services using our 5G network in April 2019, and we are continually maintaining and enhancing our 5G network coverage and service quality. The table below sets forth the number of mobile phone subscribers, including subscribers of MVNOs that lease our wireless networks, using our various digital wireless networks as of the dates indicated: As of December 31, 2025(1) 2024(1) 2023(1) (in thousands) Network 5G 17,653 17,052 15,588 LTE 6,201 7,536 8,730 WCDMA 201 325 415 Total 24,055 24,913 24,733 (1) Includes internal carrier lines and inbound roaming lines. In 2025, 2024 and 2023, our cellular services segment revenue was Won 12,552.5 billion, Won 13,318.2 billion and Won 13,123.2 billion, respectively, representing 73.4%, 74.2% and 74.5%, respectively, of our consolidated revenue. Wireless Services We offer wireless voice transmission and data transmission services to our subscribers through our backbone networks. Our wireless telecommunications services are available to our subscribers receiving service under the SK Telecom brand. In addition, customers can obtain wireless telecommunications services that operate on our network from MVNOs that lease our wireless networks. We derive revenues from our wireless telecommunications service principally through monthly plan-based fees as described in “— Rate Plans” below. We provide a voice-over-LTE service, known as our “HD Voice” service, to all of our LTE and 5G subscribers featuring high-quality voice transmission, fast call connection, voice-to-video call switching and digital content sharing during calls. We also offer our subscribers a wide range of wireless data transmissions services. Our messaging service allows our subscribers to send and receive text, graphic, audio and video messages. In addition, our subscribers can access a wide variety of digital content and services through mobile applications providing music, video, gaming, news, commerce and financial services as well as solutions that enable subscribers to access the Internet and e-mail. We intend to continue to build our wireless data services as a platform for growth, extending our portfolio of wireless data services and developing new content for our subscribers. 28 Table of Contents Through service agreements with various foreign wireless telecommunications service providers, we offer cellular global roaming services, branded as our “T-Roaming” service. Global roaming services allow subscribers traveling abroad to make and receive calls using their regular mobile phone numbers. In addition, we provide global roaming service to foreigners traveling to Korea. In such cases, we generally receive a fee from the traveler’s local wireless telecommunications service provider. Through our subsidiary SK Telink Co., Ltd. (“SK Telink”), we also operate our MVNO business under the brand “SK 7Mobile,” which we believe offers excellent quality at reasonable rates utilizing SK Telecom’s wireless networks. SK Telink is focused on developing low-cost distribution channels and targeting niche customer segments that have a lower average revenue per user than that of SK Telecom’s subscriber base. In addition, we provide interconnection service to connect our networks to domestic and international fixed-line and other wireless networks. See “— Interconnection” below. Wireless Device Sales We offer several categories of wireless devices, including smartphones and basic phones, tablets and other Internet access devices and wearable devices that are sold through an extensive distribution network, which consists of authorized exclusive dealers and independent retailers, as well as branch offices and stores directly operated by us through our wholly-owned subsidiary, PS&Marketing. As of December 31, 2025, substantially all of our mobile phone subscribers (including MVNO subscribers leasing our networks) owned smartphones that have direct access to the Internet. We purchase a substantial majority of our wireless devices from Samsung Electronics and Apple. Smartphones and Basic Phones. We offer smartphones that are enabled to utilize our digital wireless networks and run on various operating systems, such as Apple iOS and Google Android. We also offer basic phones that have the ability to access wireless Internet services. Tablets and Wearable Devices. We offer tablets and wearable devices, primarily comprising smart watches, which can access the Internet via our digital wireless networks and a Wi-Fi connection. The tablets and wearable devices run primarily on the Apple iOS and Google Android operating systems, and we provide targeted rate plans that are specific to such devices. See “— Rate Plans” below. Other Solutions and Services In addition to our cellular services and wireless device sales businesses, we provide a variety of other innovative technological solutions and services by leveraging our capabilities in telecommunications, AI and ICT technologies, and we are continuing to invest in these and other emerging new business areas, including the following: IoT Solutions and Enterprise Communication Services Through our IoT solutions business, we provide network access and enhanced services to support telemetry-type applications, which are characterized by massive machine-type communication (“mMTC”) wireless connections, to our enterprise customers. In order to promote the growth of our IoT solutions business, we deployed networks nationwide that are designed to support IoT devices, namely our high-speed LTE-M network in March 2016 and our low-cost Low-Power Wide-Area network based on LoRa technology (our “LoRa network”) in July 2016. In April 2018, we increased the battery efficiency of our IoT devices by launching our LTE Cat.M1 technology, and we have further enhanced our competitiveness in this business with our 5G network. We provide network access and customized IoT solutions to our enterprise customers. Our IoT services support devices that are used in a variety of market segments, including manufacturing, logistics, public 29 Table of Contents infrastructure, security, automotive, agriculture and data analytics as well as public institutions. For example, we provide services to transmit and store extensive data accumulated in manufacturing processes of our customers through our ultra-high speed and ultra-low latency connectivity solutions. We also offer private wireless and fixed-line networks for businesses as well as digital transformation infrastructure leveraging our 5G and edge cloud technologies. We also provide a variety of other communication solutions and services to our enterprise customers. Our key offerings in this area include IoT, security, advertising and monitoring solutions, business messaging and call services, and platforms for mobile payment, authentication and ancillary value-added services. Cloud Services We provide a comprehensive range of managed cloud services that focus on supporting cloud-based AI services in Korea. Our managed cloud services are provided in collaboration with our SK Group affiliate SK AX, which engages in B2B sales and the establishment and operation of the services, while we provide the necessary AI infrastructure and solutions. Our managed cloud services benefit from our leadership in network infrastructure in Korea and our competitive capabilities in AI, big data, data centers and information security. We plan to further strengthen our market position by developing and providing tailored AI cloud services that meet the needs of our enterprise customers. Subscription Service In August 2021, we launched a subscription-based membership service under our “T Universe” brand name. T Universe offers a wide range of lifestyle services through subscription packages. From streaming services such as YouTube Premium, Netflix and Wavve to shopping, cloud storage services such as Google One, and various partner restaurants and delivery services, customers can subscribe to a broad selection of services either as bundled packages or as standalone offerings. To enhance its service offerings, T Universe continues to pursue business partnerships with popular consumer brands and service providers, expanding the scope of its partnerships. We also plan to grow and further develop T Universe by identifying and marketing new products and services that align with customer preferences. Advertising and Curated Shopping Services We offer advertising services to businesses by leveraging our wireless and fixed-line telecommunications services platforms. Our advertising services primarily consist of display advertising on our proprietary mobile applications for smartphones, including “A. (or “A dot”) Phone” and “T Membership” (which manages our customer loyalty program under the same name). In addition, we offer a text message-based curated shopping service under our “T Deal” brand. Our customers who have consented to the T Deal service receive a daily text message on their smartphones with a link to a broad range of merchandise with significant discounts that are specially curated to maximize customer interest by utilizing AI technology and big data. AI B2C Services Through our AI B2C services business, we seek to provide innovative AI-based mobile agent services that meet our customers’ evolving needs in an increasingly connected world. In September 2023, we officially launched A., which offers the ability to verbally communicate with the user and handle a variety of tasks on the user’s smartphone, including recording and summarizing calls, managing the user’s schedules, providing real-time interpretation service during calls and recommending and playing personalized music and video contents. In August 2024, A. underwent a major update, allowing it to deliver a natural conversational experience and specialized services through various agents with enhanced search and everyday convenience features. In October 2024, we rebranded our proprietary voice call application, “T Phone,” as “A. Phone,” embedded certain of A.’s AI-enhanced service features, including the ability to record, summarize and translate calls, into the A. Phone 30 Table of Contents application. In June 2025, we introduced two additional features to A., including “A. Note,” which offers real time voice transcription and summarization services, and “A. Briefing,” which utilizes users’ personalized data to proactively provide personalized suggestions and helpful information for the users’ daily routines and tasks. We plan to continually strengthen the levels of personalization and information security, and expand the portfolio of services handled, by A., including through combination with our other service offerings as well as collaboration with our SK Group affiliates and third parties. AI B2B Services Our business customers have been increasingly seeking digital transformation by implementing AI technology, including generative AI, into their operations and business cycle. In order to meet such needs of our business customers, we have introduced various AI technology services, which we have been developing in order to improve our and our affiliated companies’ competitiveness, which are collectively referred to as “AI B2B” services (formerly referred to as “enterprise AI” services). Our AI B2B services combine AI technology with connectivity and infrastructure technologies of our core telecommunications business as well as the underlying technologies of our other new growth businesses, and principally include generative AI, AI vision, AI contact center, AI marketing, AI data and physical AI. In 2025, we also preliminarily launched “A. Biz,” a B2B version of our “A.”, an AI agent service featuring general administrative functions as well as the ability to provide assistance in a number of areas requiring professional expertise, including legal, tax, public relations, purchasing and personnel management, to business organizations. Following a period of beta tests, A. Biz is currently utilized internally as well as by a number of our SK Group affiliates. Other New Business Services We are also investing in and developing new business areas that actively integrate AI technology, including through strategic investments in, and collaboration with, leading domestic and overseas technology companies. We have also been makings investments to develop and launch GPU-as-a-service (“GPUaaS”), which would enable our enterprise customers to access GPU cloud services on an as-needed basis to develop or utilize AI services. As part of such initiative, in February 2024, we made an equity investment of US$20 million in Lambda, Inc., a GPU cloud service provider based in San Francisco, to cooperate on the development and launch of GPUaaS and AI data center solutions and services. In August 2024, we entered into a strategic partnership with Lambda, Inc. to deploy its AI cloud platform in SK Broadband’s Gasan data center, and launched our GPUaaS in January 2025. In August 2025, we launched the “Haein cluster,” comprised of more than 1,000 NVIDIA Corporation’s B200 GPUs, in SK Broadband’s Gasan data center. The Haein cluster has been selected by the MSIT for the Government’s “Sovereign AI Foundation Model Project,” which is aimed at building domestic AI foundation models with globally competitive performance, thereby reducing Korea’s reliance on foreign AI technologies. A consortium led by us has advanced to the second stage of the Sovereign AI Foundation Model Project. In June 2025, we announced the partnership with Amazon Web Services, Inc. to build an AI data center in Ulsan, Korea, with operations expected to begin in 2027. We commenced construction of such data center in September 2025. In October 2025, we signed a letter of intent and a memorandum of understanding with OpenAI, an AI research organization based in San Francisco, California, to collaborate on the construction of an AI data center in the southwest region of Korea as part of OpenAI’s Stargate project, which aims to establish a global AI infrastructure. Furthermore, we have been engaged in the research, development and promotion of AI data center solutions. As part of such initiative, in December 2024, we made an equity investment of US$200 million in Penguin Solutions Inc. (formerly known as Smart Global Holdings, Inc.), a leading designer and developer of enterprise solutions based in Milpitas, California, in order to cooperate on the development of differentiated global end-to-end AI factory and data center solutions and services. Rate Plans We offer our wireless telecommunications services on both a postpaid and prepaid basis. Substantially all of our subscribers received our wireless telecommunications services on a postpaid basis as of December 31, 2025. 31 Table of Contents Postpaid accounts primarily represent retail subscribers under contract with SK Telecom pursuant to which a subscriber is billed in advance a monthly fixed service fee in return for a monthly network service allowance and usage for outgoing voice calls and wireless data services beyond the allowance is billed in arrears, where payment of the total amount of the bill is due at the end of the month. The standard contract period for our rate plans is 24 months, although our subscribers have the option to enter into shorter term contracts or no fixed-term contract at all. We provide various subsidies and discounts, including handset subsidies, depending on the length of the contract and the subscriber’s chosen rate plan. Our prepaid service enables individuals to obtain wireless telecommunications services without a fixed-term contract by paying for all services in advance according to expected usage. We do not charge our customers for incoming calls, although we do receive interconnection charges from KT and other companies for calls from the fixed-line network terminating on our networks and interconnection revenues from other wireless network operators. See “— Interconnection” below. We also charge our customers a 10.0% value-added tax, which is included in the price of all of our rate plans. We can offset the value-added tax we collect from our customers against value-added tax refundable to us by the Korean tax authorities. We remit taxes we collect from our customers to the Korean tax authorities. We record revenues in our financial statements net of such taxes. Basic Rate Plans. We offer various postpaid account plans for mobile devices, tablets and smart watches that are designed to meet a wide range of subscriber needs and interests. Our 5G services are primarily provided through the “5GX” plans, which offer unlimited domestic voice minutes and text messaging and unlimited data transmission allowance per month and range from Won 69,000 to Won 125,000 per month. We also offer several types of lower-priced 5G rate plans, ranging from Won 39,000 to Won 59,000 per month, with smaller data transmission allowances per month compared to our 5GX plans that target subscribers who seek more affordable rate plans. Our representative smartphone rate plans for our LTE services are the “T” plans, which feature unlimited domestic voice minutes and text messaging and a fixed or unlimited data transmission allowance per month and range from Won 33,000 to Won 100,000 per month. We also offer “Direct” plans that are exclusively available through our online distribution channel, ranging from Won 27,000 to Won 76,000 per month for 5G services and at Won 22,000 per month for LTE services. Our “Voice Free” plans are available for our basic phones and feature a fixed allowance of voice minutes and 50 text messages per month with rates that range from Won 20,900 to Won 103,400 per month. We also offer a standard rate plan for Won 12,100 per month, through which the subscriber is charged per usage amount, other than on text message usage up to 50 messages per month. In October 2025, we launched six types of “air” subscription plans, a separate line of mobile subscription services offered exclusively for unlocked mobile devices through a dedicated online channel. In addition, we provide a variety of differentiated rate plans for our customer segments such as our “0 Youth” plans for smartphone users who are 34 years old or younger tailored for younger demographics, our “0 Teen” plans for teenagers who are 18 years old or younger, our “ZEM” plans for children who are 12 years old or younger, our “T Senior” LTE and 5G subscription plans for users who are 65 years or older, our “5G Happiness (Haengbok-nuri)” plans for customers with visual impairment or hearing loss and our “0 Hero” LTE plans for users who are performing mandatory military service. We also offer bundled rate discount plans combining multiple wireless devices as well as those combining our wireless services with our fixed-line telecommunications services. In addition, we offer bundled rate plans that provide discounts for family members or co-inhabitants of the same household. Data Add-on Rate Plans. We offer a variety of optional “add-on” rate plans and data coupons that are designed to meet a wide range of subscriber needs with respect to increased data usage that followed the widespread use of smartphones and faster transmission speeds. For example, for certain rate plan subscribers, we offer unlimited access to the wavve video streaming service and the Flo music streaming service through our “wavve and Data Plus” plan and “Flo and Data Plus” plan, respectively, at no additional cost, at a discounted rate or at the standard rate, depending on the subscribers’ basic rate plan. 32 Table of Contents Roaming Plans. Our representative international roaming plan for longer term travelers and provides fixed data transmission, named “baro Plan,” offers allowances of 3GB for Won 29,000, 6GB for Won 39,000, 12GB for Won 59,000 or 24GB for Won 79,000 that can be used in 195 countries. We also offer data sharing options to families travelling together and special discounts to subscribers of our “0 Youth” plans. In addition, all of our roaming plans include free high-quality data voice calls and text messages to Korea through our A. Phone application. Digital Wireless Network We offer wireless voice and data transmission services throughout Korea using digital wireless networks, primarily consisting of our 5G network, LTE network, WCDMA network, Wi-Fi network and LoRa network. We continually upgrade and increase the capacity of our wireless networks to keep pace with advancements in technology, the growth of our subscriber base and the increased usage of voice and wireless data services by our subscribers. For more information about our capital expenditures relating to our wireless networks, see “Item 5.B. Liquidity and Capital Resources — Capital Requirements — Capital Expenditures.” 5G Network. 5G is the currently dominant wireless network that enables data to be transmitted at speeds faster than our LTE network with lower latency. We began the operation of our 5G network in December 2018 on a limited basis for business customers, beginning with a few major commercial districts in Seoul and other metropolitan areas. We launched wireless service plans using the 5G network in April 2019 following the commencement of sales of the first 5G-compatible smartphones, and we continue to maintain and enhance our 5G network coverage. We currently provide full nationwide 5G network coverage across outdoor terrestrial areas and subway lines, and substantially full nationwide 5G network coverage in large buildings. Our 5G services provided a maximum data transmission speed of 2.75 Gbps. We have also deployed our 5G network for mMTC connections relating to our IoT solutions. We believe that our 5G technology and network infrastructure enable us to provide the fastest 5G data transmission network nationwide. In December 2025, the MSIT announced that our 5G network provided the fastest upload and download speeds among the three mobile network operators, KT, LG U+ and us. The nationwide average download speed of our 5G network was 1,214 Mbps compared to 1,147 Mbps for KT’s 5G network and 1,051 Mbps for LG U+’s 5G network. LTE Network. LTE technology has become widely accepted globally as the standard fourth generation technology and enables data to be transmitted at speeds faster than our WCDMA network. Since first commencing our LTE services in July 2011, we have developed and launched various upgraded LTE networks and related services providing faster network speeds, enhanced connectivity and broader coverage areas. We believe that our advanced LTE technology and dense network infrastructure enable us to provide the fastest LTE data transmission network nationwide. In December 2025, the MSIT announced that our LTE network provided the fastest upload and download speeds among the three mobile network operators, KT, LG U+ and us. The nationwide average download speed of our LTE network was 216 Mbps compared to 161 Mbps for KT’s LTE network and 141 Mbps for LG U+’s LTE network. Wi-Fi Network. Wi-Fi technology enables our subscribers with Wi-Fi-capable devices such as smartphones, laptops and tablet computers to access mobile Internet. We started to build Wi-Fi access points in 2010 and, as of December 31, 2025, we had more than 60,000 Wi-Fi access points in public areas such as shopping malls, restaurants, coffee shops, subways and airports where, generally, the demand for high-speed wireless Internet service is high. While each Wi-Fi access point typically has a radius of approximately 20-30 meters, some of our Wi-Fi hot zones, which have multiple Wi-Fi access points, including those installed at public transportation facilities and amusement parks, have much wider service areas. LoRa Networks. A Low-Power Wide-Area network based on LoRa technology is a type of telecommunications network designed to support communication among IoT devices. It can transmit data over 33 Table of Contents tens of kilometers while consuming much less power than LTE networks, lowering costs for connectivity as well as lowering battery power usage. We completed the nationwide deployment of our LoRa network in July 2016. We expect that our LoRa network will provide the infrastructure necessary for the growth of not only our own IoT solutions business but also the IoT industry as a whole. Network Infrastructure The principal components of our wireless networks are: • base stations, which are physical locations equipped with transmitters, receivers and other equipment that communicate by radio signals with wireless handsets within range of the cell (typically a 3 to 40 kilometer radius); • switching stations, which switch voice and data transmissions to their proper destinations, which may be, for instance, a mobile phone of one of our subscribers (for which transmissions would originate and terminate on our wireless networks), a mobile phone of a KT or LG U+ subscriber (for which transmissions would be routed to KT’s or LG U+’s wireless networks, as applicable), a fixed-line telephone number (for which calls would be routed to the public switched telephone network of a fixed-line network operator), an international number (for which calls would be routed to the network of a long distance service provider) or an Internet site; and • transmission lines, which link base stations to switching stations and switching stations with other switching stations. As of December 31, 2025, our 5G, LTE and WCDMA networks had an aggregate of 58,567 base stations. To date, we have purchased substantially all of the equipment for our networks from Samsung Electronics, Ericsson-LG and Nokia. Most of the transmission lines we use, including virtually all of the lines linking switching stations, as well as a portion of the lines linking base stations to switching stations, comprise optical fiber lines that we own and operate directly. However, we have not undertaken to install optical fiber lines to link every base station and switching station. In places where we have not installed our own transmission lines, we have leased lines from KT and LG U+. We intend to increase the efficiency of our network utilization and provide optimal services by internalizing transmission lines. We use a wireless network surveillance system. This system oversees the operation of base stations and allows us to monitor our main equipment located throughout the country from one monitoring station. The automatic inspection and testing provided to the base stations lets the system immediately rebalance to the most suitable setting, and the surveillance system provides for automatic dispatch of repair teams and quick recovery in emergency situations. Marketing, Distribution and Customer Service Marketing. Our marketing strategy is focused on offering solutions tailored to the needs of our various customer segments, promoting our brand and leveraging our extensive distribution network. Our marketing plan includes a coordinated program of television, print, radio, outdoor signage, Internet and point-of-sale media promotions designed to relay a consistent message across all of our markets. We market our wireless products and services under the “T” brand, which signifies the centrality of “Telecommunications” and “Technology” to our business and also seeks to emphasize our commitment to providing “Top” quality, “Trustworthy” products and services to our customers. We have implemented certain information technology improvements in connection with our marketing strategy, including customer management systems, as well as more effective information security controls. We believe these upgrades have enhanced our ability to process and utilize marketing- and subscriber-related data, 34 Table of Contents which, in turn, has helped us to develop more effective and targeted marketing strategies. We currently operate a customer information system designed to provide us with an extensive customer database. Our customer information system includes a billing system that provides us with comprehensive account information for internal purposes and enables us to efficiently respond to customer requests. Our customers can also change their rate plans, verify the charges accrued on their accounts, receive their bills online and send text messages to our other subscribers through our website at www.tworld.co.kr and through our “T world” mobile application. We strive to improve subscriber retention through our T Membership program, which is a membership service available to our wireless subscribers. Our T Membership program provides various membership benefits to its members such as discounts with our membership partners for dining, shopping, entertainment and travel, membership points accumulation, access to our online membership shopping mall and invitations to various promotional events. Although our competitors also have similar membership programs, we believe that our T Membership program has a competitive advantage over our competitors’ membership programs due to our large subscriber base and breadth of membership benefits. Distribution. We use a combination of an extensive network, including branch offices and stores, directly operated by us through our subsidiary, PS&Marketing, more than 2,500 authorized exclusive dealers and an extensive network of independent retailers in order to increase subscriber growth while reducing subscriber acquisition costs. In addition, we operate an online distribution channel, “T Direct Shop,” through which subscribers can conveniently purchase wireless devices and subscribe to our services online. We also operate a dedicated online shop on 11st, our former subsidiary Eleven Street’s e-commerce marketplace. In light of increasing customer preference for online service, the level of distribution of our wireless devices and our services through online channels has significantly increased in recent years. We intend to continue to develop our online distribution channel to leverage our offline distribution capabilities to provide convenience and additional value to our subscribers. For example, subscribers purchasing wireless devices through T Direct Shop can opt to pick up their devices at one of our offline stores. Currently, authorized dealers are entitled to an initial commission for each new subscriber registered by the dealer, as well as an average ongoing commission calculated as a percentage of that subscriber’s monthly plan-based rate for the first five years. In order to strengthen our relationships with our exclusive dealers, we offer a dealer financing plan, pursuant to which we provide to each authorized dealer a loan of up to Won 4.0 billion (Won 5.0 billion if collateral is pledged) which can be used for operating expenditures with a repayment period of up to 11 months. We also provide loans to our authorized dealers for financing deposits and key money in connection with securing retail space with a repayment period of up to 30 months. As of December 31, 2025, we had an aggregate of Won 61.1 billion outstanding in loans to authorized dealers. Customer Service. We provide high-quality customer service directly through our two subsidiaries, Service Ace Co., Ltd. and Service Top Co., Ltd., rather than rely on outsourcing. SK O&S Co., Ltd. operates our switching stations and related transmission and power facilities and offers quality customer service primarily to our business customers. We have held the top position with respect to our telecommunications service in Korea’s leading three customer satisfaction indices, the National Customer Satisfaction Index, the Korean Customer Satisfaction Index and the Korean Standard-Service Quality Index, for 28 years, 27 years and 26 years, respectively. Fixed-line Telecommunications Services We offer fixed-line telephone, broadband Internet and advanced media platform services (including IPTV and cable TV services), and business communications and related infrastructure services, through our fixed-line telecommunications services segment. Our fixed-line telecommunications services are provided by our 35 Table of Contents subsidiary, SK Broadband. The following table sets forth historical information about our subscriber base for our fixed-line telecommunications services for the periods indicated: As of December 31, 2025 2024 2023 (in thousands) Fixed-Line Telephone (including VoIP)(1) 3,269 3,364 3,464 Broadband Internet(2) 7,238 7,156 6,926 IPTV(3) 6,721 6,803 6,728 Cable TV 2,729 2,806 2,821 (1) Includes subscribers to VoIP services of SK Broadband. (2) Excludes dedicated broadband Internet lines for Internet cafes. (3) Includes subscribers to SK Broadband’s B tv service and video-on-demand only service subscribers. In 2025, 2024 and 2023, our fixed-line telecommunications services segment revenue was Won 4,191.1 billion, Won 4,075.4 billion and Won 3,928.0 billion, respectively, representing 24.5%, 22.7% and 22.3%, respectively, of our consolidated revenue. As part of our efforts to enhance our capabilities and increase our market share in the fixed-line business, we completed the Tbroad Merger in April 2020. In November 2024, in order to enhance management efficiency and strengthen our control over SK Broadband, we entered into an agreement to acquire an additional 24.8% equity interest in SK Broadband from minority shareholders. Such transaction was completed in May 2025. We owned approximately 99.1% of SK Broadband’s total outstanding shares as of December 31, 2025. Furthermore, in March 2026, in order to enhance management efficiency and strengthen enterprise value through greater strategic flexibility, we entered into an agreement to acquire the remaining 0.9% equity interest in SK Broadband from minority shareholders. Such transaction is currently pending subject to regulatory approval and other customary closing conditions. See “Item 3.D. Risk Factors — Risks Relating to Our Business — Competition may reduce our market share and harm our business, financial condition and results of operations.” Fixed-line Telephone Services Our fixed-line telephone services comprise local, domestic long distance, international long distance and VoIP services. VoIP is a technology that transmits voice data through an Internet Protocol network. As of December 31, 2025, we had approximately 3.3 million fixed-line telephone subscribers (including subscribers to VoIP services of SK Broadband). Our fixed-line telephone services are primarily offered under the “B phone” brand name. A portion of our fixed-line telephone services were previously provided through the VoIP services of our subsidiary SK Telink that targeted corporate customers, which business was acquired by SK Broadband in April 2021. Broadband Internet Access Services Our broadband Internet access network covered a substantial majority of households in Korea as of December 31, 2025. As of December 31, 2025, we had approximately 7.2 million broadband Internet access subscribers. We offer broadband Internet access products with various throughput speeds, ranging from optical LAN service, which provides maximum data transmission speeds of up to 100 Mbps, to “Giga Premium” and “Giga Premium×10,” which provide maximum data transmission speeds of up to 1 Gbps and 10 Gbps, respectively. Advanced Media Platform (including IPTV and Cable TV Services) As part of our initiative to be the leading next-generation platform provider, we provide an advanced media platform with various media content and service offerings. 36 Table of Contents We have offered video-on-demand services since 2006 and launched real-time IPTV services in 2009. We currently offer IPTV services under the brand name “B tv” with access to as many as 272 high definition channels depending on the subscription service as of December 31, 2025, as well as pay-per-view and subscription-based video-on-demand services providing a wide range of media content, including recent box office movie releases, popular U.S. and other foreign TV shows and various children’s TV programs. We also offer “B tv UHD,” which is an ultra-high definition IPTV service and has a resolution that is four times as high as the standard high definition broadcasting service in the IPTV industry. As of December 31, 2025, we had approximately 6.7 million IPTV subscribers. Since 2018, we have unveiled a number of smart set-up boxes that incorporate voice recognition and command capabilities as well as AI-based services. In December 2023, we introduced “AI B tv,” Korea’s first AI-powered personalized IPTV service. Once a set top box is turned on, AI B tv automatically recognizes the user and provides hyper-personalized content experience including recommending video-on-demand and other content based on the user’s viewing history analyzed through AI technology. We plan to integrate T-commerce capabilities into AI B tv and allow users to concurrently search for and purchase the apparel and accessories that appear in the video-on-demand content, which are recognized through AI technology. We also plan to further develop and improve our AI B tv service by integrating A. and generative AI technology. In September 2024, we introduced “B tv A. Service,” a new AI voice command service which utilizes A.’s large-language model and allows customers to explore content and receive recommendations. Following the Tbroad Merger, we have been offering cable TV services under the “B tv Cable” brand with access to as many as 226 channels. As of December 31, 2025, we had approximately 2.7 million cable TV subscribers. We also offer advertising services on our advanced media platform, primarily consisting of advertisements on video-on-demand and streaming contents and our TV channels. In addition, in May 2024, we began to offer access to the over-the-top content offerings of Netflix through our IPTV set-top boxes at a bundled discount with our IPTV subscriptions. SK Broadband also operates two TV channels and co-produces original television entertainment contents through our indirect subsidiary Media S. In December 2025, we entered into an agreement to sell our entire equity stake in SK Stoa, which operates our T-commerce business, and Media S to Rapport Labs Inc., a Korea-based e-commerce company, as part of our ongoing strategy to streamline and optimize our overall business portfolio. Such transaction is currently pending subject to regulatory approval and other customary closing conditions. We continue to expand the scope of our media services and content offerings to provide our subscribers with a vast library of high-quality content that can be accessed through our wireless networks and our fixed-line network, which we believe will also increase the appeal of our advanced media platform to businesses as an advertising platform. Business Communications and Related Infrastructure Services Through SK Broadband, we offer business communications and related infrastructure services to our business customers, including corporations and government entities. Our business communications and related infrastructure services offered by SK Broadband include leased line solutions, Internet data center solutions and network solution services. Our leased line solutions are exclusive lines that allow point-to-point connection for voice and data traffic between two or more geographically separate points. We hold a license to operate leased line services on a nationwide basis in Korea and also use international transmission lines to provide leased line services to other countries. Our leased line services enable high volumes of data to be transmitted swiftly and reliably. We also 37 Table of Contents provide back-up storage for transmitted data. Through our Internet data centers, we provide our business subscribers with server-based support including co-location, dedicated server hosting and cloud computing services. In June 2025, SK Broadband acquired the business operations of the Pangyo Data Center from SK Inc. for Won 506.8 billion as part of its initiative to expand its data center operations and generate synergy. Our network solution service utilizes our network infrastructure and voice platform to provide 24-hour monitoring and control of our customers’ networks. Through this service, we conduct remote monitoring of our customers’ data and voice communications infrastructure and network and traffic conditions, and carry out preventive examinations and on-site visits. Rate Plans For our residential customers, we offer both bundled rate plans for a combination of our fixed-line service offerings as well as individual rate plans for each separate service offering. Bundled rate plans are offered at a discount compared to subscribing to the same services through individual rate plans. Approximately 87% of subscribers to our broadband Internet services subscribe to two or more of our services through our bundled rate plans. Bundled rate plans for a combination of fixed-line telephone, broadband Internet access and IPTV or cable TV services, which are subject to a contract of one to three years, range from Won 33,000 to Won 111,100 per month, depending on the services included and the length of the contract. We also offer bundled rate plans combining our fixed-line telecommunications services with our wireless services, the physical security services of SK Shieldus Co., Ltd., and subscriptions to Netflix, as well as bundled rate plans that provide discounts for family members or co-inhabitants of the same household. Our “5,000 minute” plan for subscribers to our fixed-line telephone service features 5,000 voice minutes for domestic land-to-land calls for a fixed rate and range from Won 7,700 to Won 11,550 per month depending on whether or not the subscriber opts for a long-term contract and if so, the length of the contract period. We offer individual fixed-rate plans for our broadband Internet access service that range from Won 30,800 to Won 104,500 per month depending on the data throughput speed and existence and length of a contract. We offer individual fixed-rate plans for our IPTV and cable TV services that range from Won 4,400 to Won 50,600 per month depending on the number of channels provided and existence and length of a contract. In addition, subscribers can purchase individual videos on demand or subscribe to certain paid content on a periodic basis. With respect to our business communications and related infrastructure services, we offer rates that are tailored to the specific needs of our business customers. We also charge certain installation fees and equipment rental fees as well as other ancillary fees with respect to certain of our fixed-line telecommunications services. Marketing, Distribution and Customer Service We focus on bringing our fixed-line telephone, broadband Internet and advanced media platform services (including IPTV and cable TV services) to residential users, and various business communications and related infrastructure services to corporate users. We market our fixed-line telecommunications products and services under the “B” brand. Our “B” brand signifies our pursuit of creating a “Borderless” media ecosystem with “Beloved” content offerings to transform our business to go “Beyond” simply offering connectivity to customers. It also seeks to emphasize our commitment to stand “Beside” our customers to “Bridge” their worlds, leading to “Bravo” and “Blissful” customer experience. Our “B” brand also strengthens our shared identity with our wireless service’s “T” brand. We operate an extensive distribution network, including regional marketing branch offices and numerous customer centers, large retail stores and authorized dealers across Korea, in order to increase subscriber growth while reducing subscriber acquisition costs. In addition, SK Telecom’s direct retail stores and authorized dealers for wireless telecommunications services also market our fixed-line telephone, broadband Internet and advanced media platform services (including IPTV and cable TV services), which we believe has contributed to the increase in the number of subscribers to such services. We have contracts with our customer centers to sell our services exclusively. These centers receive a commission for each service contract and installation contract 38 Table of Contents secured. Customer centers often enter into sub-contracts with smaller distribution outlets within their area to increase their sales coverage and engage in telemarketing efforts. Authorized dealers are entitled to an initial commission for each new subscriber registered by the dealer. In addition, we operate an online distribution channel, “B Direct Shop,” through which subscribers can conveniently subscribe online to our pay TV, broadband Internet and residential fixed-line telephone services. In light of increasing customer preference for online service, the level of distribution of our services through the B Direct Shop has consistently increased in recent years. We intend to continue to develop our online distribution channel to leverage our offline distribution capabilities to provide convenience and additional value to our subscribers. Sales to business subscribers are handled through our in-house sales group as well as a small-scale distribution network. Our in-house sales group focuses on large business clients such as major corporations, public institutions and governmental agencies. Our small-scale distribution network, on the other hand, targets smaller business clients such as small businesses and sole proprietorship businesses. Other Businesses We strive to continually diversify our products and services and develop new businesses that we believe are complementary to our existing products and services, which we include in our other businesses segment. In 2025, 2024 and 2023, the revenue of our other businesses segment, which primarily consisted of our T-commerce and former portal service businesses, was Won 355.6 billion, Won 547.0 billion and Won 557.3 billion, respectively, representing 2.1%, 3.0% and 3.2%, respectively, of our consolidated revenue. See “Item 5.A. Operating Results — Overview — Operational Efficiency.” We operate a T-commerce network, “SK stoa,” through our consolidated subsidiary SK Stoa, which offers a broad assortment of goods and services through pre-recorded television programming. The goods and services promoted on SK stoa’s T-commerce programming can be purchased through telephone orders, SK stoa’s mobile application or online open marketplace, or a virtual application appearing on the television screen using the viewer’s remote controller. Since 2019, SK Stoa has offered searchable shopping programming that is available to viewers at their convenience by utilizing video-on-demand capabilities. SK Stoa also operates several private fashion and health supplement brands. SK stoa also acts as the exclusive T-commerce distributor for certain products and services of SK Group companies, such as food, electronics, home appliances and car rentals. In December 2025, we entered into an agreement to sell our entire equity stake in SK Stoa and Media S, which operates two TV channels and co-produces original television entertainment contents as described above, to Rapport Labs Inc. as part of our ongoing strategy to streamline and optimize our overall business portfolio. Such transaction is currently pending subject to regulatory approval and other customary closing conditions. Prior to the completion of the disposal transactions described below, we also offered online portal services under our “Nate” brand name through our former subsidiary NATE Communications Corporation, and online corporate employment benefits management and training services for Korean businesses and public institutions through our former indirect subsidiary SK M&Service. In December 2024, as part of our efforts to increase our operational efficiency and re-balance our business areas, we entered into agreements with Samgu Inc. and its affiliates to dispose of our 100% equity interest in NATE Communications Corporation and a 70% equity interest in SK M&Service, as well as our interest in a former non-consolidated associate. The disposals of NATE Communications Corporation, SK M&Service and F&U Credit Information were completed in January 2025, February 2025 and April 2025, respectively. See “Item 5.A. Operating Results — Overview — Operational Efficiency.” Interconnection Our wireless and fixed-line networks interconnect with the public switched telephone networks operated by KT and SK Broadband and, through their networks, with the international gateways of KT and LG U+, as well as 39 Table of Contents the networks of the other wireless telecommunications service providers in Korea. These connections enable our subscribers to make and receive calls from telephones outside our networks. Under Korean law, certain service providers, including us, are required to permit other service providers to interconnect to their networks. If a new service provider desires interconnection with the networks of an existing service provider but the parties are unable to reach an agreement within 90 days, the new service provider can appeal to the KMCC. Domestic Calls Guidelines issued by the MSIT require that all interconnection charges levied by a regulated carrier take into account (i) the actual costs to that carrier of carrying a call or (ii) imputed costs. The MSIT determines interconnection rates applicable to each carrier based on changes in traffic volume, taking into account other factors such as research results, competition and trends in technology development. Wireless-to-Fixed-line. According to our interconnection arrangement with KT, for a call from our wireless network to KT’s fixed-line network, we collect the usage rate from our wireless subscriber and in turn pay KT the interconnection charges. Similarly, KT pays interconnection charges to SK Broadband for a call from KT’s wireless network to SK Broadband’s fixed-line network. The interconnection rate applicable to both KT and SK Broadband was Won 6.73 per minute, Won 6.89 per minute and Won 7.22 per minute for 2025, 2024 and 2023, respectively. Fixed-line-to-Wireless. The MSIT determines interconnection arrangements for calls from a fixed-line network to a wireless network. For a call initiated by a fixed-line user to one of our wireless subscribers, the fixed-line network operator collects our usage fee from the fixed-line user and remits to us an interconnection charge. Interconnection with KT accounts for substantially all of our fixed-line-to-wireless interconnection revenue and expenses. The interconnection rate paid by fixed-line network service providers to each wireless network service provider was Won 8.15 per minute, Won 8.55 per minute and Won 9.17 per minute for 2025, 2024 and 2023, respectively. Wireless-to-Wireless. Interconnection charges also apply to calls between wireless telephone networks in Korea. Under these arrangements, the operator originating the call pays an interconnection charge to the operator terminating the call. The applicable interconnection rate is the same as the fixed-line-to-wireless interconnection rate set out in the paragraph above. Our revenues from the wireless-to-wireless interconnection charges were Won 341.5 billion in 2025, Won 370.1 billion in 2024 and Won 401.3 billion in 2023. Our expenses from these charges were Won 335.4 billion in 2025, Won 364.9 billion in 2024 and Won 392.4 billion in 2023. International Calls and International Roaming Arrangements With respect to international calls, if a call is initiated by our wireless subscribers, we bill the wireless subscriber for the international charges of KT, LG U+ or SK Broadband, and we receive interconnection charges from such operators. If an international call is received by our subscriber, KT, LG U+ or SK Broadband pays interconnection charges to us based on our imputed costs. To complement the services we provide to our subscribers in Korea, we offer international voice and data roaming services. We charge our subscribers usage fees for global roaming service and, in turn, pay foreign wireless network operators fees for the corresponding usage of their network. For a more detailed discussion of our global roaming services, see “— Wireless Services” above. Competition We operate in highly saturated and competitive markets, and we believe that our subscriber growth is affected by many factors, including the expansion and technical enhancement of our networks, the development 40 Table of Contents and deployment of new technologies, the effectiveness of our marketing and distribution strategy, the quality of our customer service, the introduction of new products and services, competitive pricing of our rate plans, new market entrants and regulatory changes. Historically, there has been considerable consolidation in the telecommunications industry, resulting in the current competitive landscape comprising three mobile and fixed network operators in the Korean market, KT, LG U+ and us. Each of our competitors has substantial financial, technical, marketing and other resources to respond to our business offerings. The following table shows the market share information, based on number of subscribers, as of December 31, 2025, for the following markets. Market Share (%) SK Telecom KT LG U+ Others Mobile phone(1) 41.6 % 30.8 % 27.6 % — % Fixed-Line Telephone (including VoIP) 15.6 51.6 18.1 14.7 Broadband Internet 28.7 40.3 22.1 8.9 Pay TV (2) 25.9 (3) 36.7 (4) 25.1 (5) 12.2 (1) Includes MVNO subscribers that lease the wireless networks of the respective mobile network operator. (2) Includes video-on-demand only service subscribers. Market share is expressed as a percentage of the pay TV market (which includes IPTV, cable TV and satellite TV). (3) Consists of 18.4% from our IPTV service and 7.5% from our cable TV service. (4) Consists of 26.2% from KT’s IPTV service, 7.1% from its satellite TV service provided through KT Skylife and 3.4% from KT’s cable TV service provided through HCN, which was acquired by KT in August 2021. (5) Consists of 15.7% from LG U+’s IPTV service and 9.4% from its cable TV service provided through LG HelloVision, a subsidiary of LG U+. Cellular Services As of December 31, 2025, we had 23.5 million mobile phone subscribers, representing a market share of approximately 41.6%, including MVNO subscribers leasing our networks. As of December 31, 2025, KT and LG U+ had 17.4 million and 15.6 million mobile phone subscribers, respectively, representing approximately 30.8% and 27.6%, respectively, of the total number of mobile phone subscribers in Korea on such date, each including MVNO subscribers leasing its networks. In 2025, we had 1.9 million activations and 2.9 million deactivations. In 2025, the monthly churn rate in our wireless telecommunications business ranged from 0.7% to 2.3%, with an average monthly churn rate of 1.1%, which increased from 0.8% in 2024. The increases in deactivations and average monthly churn rate in 2025 compared to 2024 were mainly due to the cybersecurity incident of which we became aware in April 2025 as described above. See “— Malicious and abusive Internet practices could impair our services and we may be subject to significant legal and financial exposure, damage to our reputation and a loss of confidence of our customers.” Our competitors for subscriber activations include MVNOs, including MVNOs that lease our networks. MVNOs generally provide rate plans that are relatively cheaper than similar rate plans of the wireless network providers from which they lease their networks, including us. Currently, 15 MVNOs provide wireless telecommunications services using the networks leased from us. As of December 31, 2025, MVNOs had a combined market share of 18.3%, of which MVNOs leasing our networks represented 3.1%, MVNOs leasing KT’s networks represented 7.0% and MVNOs leasing LG U+’s networks represented 8.1%. In recent years, a number of new entrants have entered the MVNO business, including affiliates of leading financial institutions in Korea. Some of these new entrants have engaged in aggressive marketing campaigns and 41 Table of Contents promotional discounts while leveraging the brand power of their affiliates as part of their efforts to gain subscribers. Partly as a result of such efforts, the combined market share of MVNOs has generally increased in recent years, including from 16.9% as of December 31, 2024 to 18.3% as of December 31, 2025, in terms of number of mobile phone subscribers. In January 2025, the Government announced a number of new policy measures to strengthen the competitiveness of MVNOs, including lowering the cost of leasing networks from wireless network providers (including us) and providing support for the emergence of “full MVNOs” possessing their own core network infrastructures and telephone platform operations. We cannot assure you that such policy measures will not lead to further increases in the combined market share of MVNOs or encourage new MVNOs to enter the market.In addition, other companies may enter the wireless network services market. See “— Law and Regulation — Frequency Allocation” and “Item 3.D. Risk Factors — Risks Relating to Our Business — Our businesses are subject to various types of Government regulation, and any change in Government policy relating to the telecommunications industry could have an adverse effect on our business, financial condition and results of operations.” For a description of the risks associated with the competitive environment in which we operate, see “Item 3.D. Risk Factors — Risks Relating to Our Business — Competition may reduce our market share and harm our business, financial condition and results of operations.” Historically, competition in the wireless telecommunications business had caused us to significantly increase our marketing and advertising expenses from time to time depending on the prevailing competitive landscape, with marketing expenses as a percentage of SK Telecom’s revenue, on a separate basis, reaching a peak of 28.2% in 2012. Such percentage was 24.2% in 2023, 22.8% in 2024 and 24.1% in 2025. We believe that the maturity of the overall wireless telecommunication market has contributed to the general stabilization of our marketing expenses in recent years. We face competition from KT and LG U+ as well as other platform service providers in our other cellular service businesses. For example, our Smart Home service competes with KT’s Giga IoT Home service and LG U+’s IoT@Home service. Fixed-Line Telecommunications Services Our fixed-line telephone service competes with KT and LG U+, as well as other providers of VoIP services. As of December 31, 2025, our market share of the fixed-line telephone and VoIP service market was 15.6% (including the services provided by SK Broadband) in terms of number of subscribers compared to KT with 51.6% and LG U+ with 18.1%. We are the second-largest provider of broadband Internet access services in Korea in terms of both revenue and subscribers, and our network covered a substantial majority of households in Korea as of December 31, 2025. As of December 31, 2025, our market share of the broadband Internet market was 28.7% in terms of number of subscribers compared to KT with 40.3% and LG U+ with 22.1%. Our IPTV and cable TV services compete with other providers of pay TV services, including KT, LG U+ and cable companies. As of December 31, 2025, our market share of the pay TV market (which includes IPTV, cable TV and satellite TV) was 25.9% compared to KT with 36.7% (including its IPTV, cable TV and satellite TV services) and LG U+ with 25.1% (including its IPTV and cable TV services), and the collective market share of other pay TV providers was 12.2%. Our market shares in the broadband Internet and pay TV markets in 2025 were marginally and negatively affected by the impact of the above-mentioned cybersecurity incident, as a significant portion of our customers of these services subscribe to packages that combine our mobile phone services with one or both of these services. Furthermore, our IPTV and cable TV services are facing an increasing level of competition from global operators of online video streaming platforms, such as YouTube, Netflix, Disney Plus and Apple TV, leading domestic video streaming platforms such as TVING, Coupang Play, Wavve (which is seeking to merge with TVING pursuant to a memorandum of understanding entered into in December 2023) and Watcha, and the video contents offered by leading domestic and global internet search, communications and social media platforms including NAVER, Kakao and Instagram, as such services continue to become increasingly popular to serve as a substitute to traditional television programming. 42 Table of Contents Over the past decade, the Korean fixed-line telecommunications industry has gone through significant consolidation involving major pay television service providers. We completed the Tbroad Merger in April 2020, following which we became the second-largest pay TV provider in Korea in terms of number of subscribers as of December 31, 2025. In December 2019, LG U+ acquired a majority equity stake in LG HelloVision. In August 2021, KT acquired HCN, a major Korean cable TV service provider, through its subsidiary KT Skylife. Such transactions, as well as further consolidation in the fixed-line telecommunications industry, may result in increased competition, as the entities emerging from such consolidation and other remaining players in the industry may actively pursue expanding or protecting their respective market shares. Other Investments and Relationships We have investments in a number of other businesses and companies and have entered into various business arrangements with other companies. For example, in July 2022, we entered into a strategic alliance with Hana Financial Group, a leading financial holding company in Korea with subsidiaries having significant presences in commercial banking, credit card business, securities brokerage and insurance, among others, to seek synergies through convergence between finance and ICT technology. As part of such strategic alliance, we transferred the entirety of our 15.0% interest in HanaCard for Won 330.0 billion in July 2022 and acquired 8,630,949 shares of Hana Financial Group (representing a 2.9% interest) for Won 330.0 billion between July and November 2022, and HanaCard acquired 1,307,471 common shares of us (representing a 0.6% interest) for Won 68.4 billion between July and September 2022. See also “— Cellular Services — Other Solutions and Services — Other New Businesses.” Law and Regulation Overview Korea’s telecommunications industry is subject to comprehensive regulation by the MSIT, which is responsible for information and telecommunications policies. The MSIT regulates and supervises a broad range of communications issues, including: • entry into the telecommunications industry; • scope of services provided by telecommunications service providers; • allocation of radio spectrum; • setting of technical standards and promotion of technical standardization; • rates, terms and practices of telecommunications service providers; • interconnection and revenue-sharing between telecommunications service providers; • research and development of policy formulation for information and telecommunications; and • competition among telecommunications service providers. The MSIT is charged with regulating information and telecommunications, and the KMCC is charged with regulating the public interest aspects of and fairness in broadcasting and telecommunications. Telecommunications service providers are currently classified into two categories: network service providers and value-added service providers. We are classified as a network service provider because we provide telecommunications services with our own telecommunications networks and related facilities. As a network service provider, we were previously required to obtain a license from the MSIT for the services we provide. However, an amendment to the Telecommunications Business Act, pursuant to which companies meeting certain regulatory criteria may become a network service provider without a separate license requirement, went into effect in June 2019. Our licenses permit us to provide cellular services, third generation wireless telecommunications services using WCDMA technology, fourth generation wireless telecommunications services using LTE technology and fifth generation wireless telecommunications services using 5G technology. 43 Table of Contents The MSIT may revoke our licenses or suspend any of our businesses if we fail to comply with its rules, regulations and corrective orders, including the rules restricting beneficial ownership and control and corrective orders issued in connection with any violation of rules restricting beneficial ownership and control or any violation of the conditions of our licenses. Alternatively, in lieu of suspension of our business, the MSIT may levy a penalty surcharge of up to 3.0% of the average of our annual revenue for the preceding three fiscal years. A network service provider that wants to cease its business or dissolve must notify its users 60 days prior to the scheduled date of cessation or dissolution and obtain MSIT approval. In the past, the Government has stated that its policy was to promote competition in the Korean telecommunications market through measures designed to prevent the dominant service provider in any such market from exercising its market power in such a way as to prevent the emergence and development of viable competitors. While all network service providers are subject to MSIT regulation, we are subject to increased regulation because of our position as the dominant wireless telecommunications services provider in Korea. Competition Regulation The KMCC is charged with ensuring that network service providers engage in fair competition and has broad powers to carry out this goal. If a network service provider is found to be in violation of the fair competition requirement, the KMCC may take corrective measures it deems necessary, including, but not limited to, prohibiting further violations, requiring amendments to the articles of incorporation or to service contracts with customers, requiring the execution or performance of, or amendments to, interconnection agreements with other network service providers and prohibiting advertisements to solicit new subscribers. The KMCC is required to notify the Minister of the MSIT upon ordering certain corrective measures. In addition, we may also be designated as a “market-dominating business entity” by the relevant authorities under the Fair Trade Act, based on a case-by-case assessment of factors such as our market share, barriers to entry and the relative scale of competitors. If so designated, we would be prohibited from engaging in conduct that could be deemed an abuse of such position, including unreasonably determining, maintaining or altering service rates, unreasonably controlling the rendering of services, unreasonably interfering with business activities of other business entities, hindering unfairly the entry of newcomers or substantially restricting competition to the detriment of the interests of consumers. Because we are a member company of the SK Group, which is a large business group as designated by the KFTC, we are subject to the following restrictions under the Fair Trade Act: • Restriction on debt guarantee among affiliates. Any affiliate within the SK Group may not guarantee the debts of another domestic affiliate, except for certain guarantees prescribed in the Fair Trade Act, such as those relating to the debts of a company acquired for purposes of industrial rationalization, bid deposits for overseas construction work or technology development funds. • Restriction on cross-investment. A member company of the SK Group may not acquire or hold shares in an affiliate belonging to the SK Group that owns shares in the member company. • Restrictions on circular investments. A member company of the SK Group may not acquire or hold shares which would constitute “circular investments” in an affiliate company which also forms part of the SK Group where “circular investments” refer to a cross-affiliate shareholding relationship under which three or more affiliate companies become connected through cross affiliate shareholdings by owning shares in other affiliates or by becoming an entity whose shares are owned by other affiliates. • Public notice of board resolution on large-scale transactions with specially related persons. If a member company of the SK Group engages in a transaction with a specially related person in an amount exceeding the lesser of (1) Won 10 billion and (2) 5.0% of the larger of the total capital or capital stock of the member company (provided, however, in cases where 5.0% of the total capital or 44 Table of Contents capital stock of the member company is less than Won 500 million, the threshold set forth in (2) above is set at Won 500 million), the transaction must be approved by a resolution of the member company’s board of directors and the member company must publicly disclose the transaction. • Restrictions on investments by subsidiaries and sub-subsidiaries of holding companies. The Fair Trade Act prohibits subsidiaries of holding companies from investing in, or holding shares of common stock of, domestic affiliates that belong to the same large business group, unless such domestic affiliates are their own subsidiaries. Furthermore, any subsidiaries of a holding company’s subsidiaries (“sub-subsidiaries”) are prohibited from investing in, or holding shares of common stock of, domestic affiliates that belong to the same large business group, unless all shares issued by the affiliates are held by the sub-subsidiary. Therefore, we and other subsidiaries of SK Inc. may not invest in any domestic affiliate that is also a member company of the SK Group, except in the case where we invest in our own subsidiary or where another subsidiary of SK Inc. invests in its own subsidiary. • Public notice of the current status of a business group. Under the Fair Trade Act and the Enforcement Decree thereof, a member company of the SK Group must publicly disclose the general status of the SK Group, including the name, business scope and financial status of affiliates, information on the officers of affiliates, information on shareholding and cross-investments between member companies of the SK Group, information on transactions with certain related persons and, if a member company engages in a transaction with an affiliated company in the amount of 5.0% or more of the member company’s quarterly sales or Won 5.0 billion or more, information on transactions with such affiliated company on a quarterly basis. Rate Regulation Network service providers whose sales proceeds exceed the amount prescribed by law must report to the MSIT the rates and contractual terms for each type of service they provide. Under the current reporting requirement, which does not apply to other network service providers with respect to the rates they provide, the MSIT has fifteen days to object to any new rates and terms of service reported by us, and we may implement such new rates and terms of service after the fifteen-day period expires in the absence of the MSIT’s objection. Furthermore, in 2007, the Government announced a “road map” highlighting revisions in regulations to promote deregulation of the telecommunications industry. In accordance with the road map and pursuant to the Combined Sales Regulation, promulgated in May 2007, telecommunications service providers in Korea are permitted to bundle their services, such as wireless data transmission service, wireless voice transmission service, broadband Internet access service, fixed-line telephone service and IPTV service, at a discounted rate; provided, however, that we and KT, each of which holds a significant market share in the telecommunications industry, allow other competitors to employ the services provided by us and KT, respectively, so that such competitors can provide similar discounted package services. In September 2007, the regulations and provisions under the Telecommunications Business Act were amended to permit licensed transmission service providers to offer local, domestic long-distance and international telephone services, as well as broadband Internet access and Internet phone services, without additional business licenses. Moreover, an MVNO system under which the MSIT may designate and obligate certain wireless telecommunications services providers to allow an MVNO, at such MVNO’s request, to use their telecommunications network facilities at a rate mutually agreed upon that complies with the standards set by the MSIT became effective on March 14, 2017 under the amended Telecommunications Business Act. We are currently the only wireless telecommunications services provider obligated to allow other wireless telecommunications services providers to use our telecommunications network facilities. Currently, 15 MVNOs provide wireless telecommunications services using the networks leased from us. On October 1, 2014, the MDDIA, enacted for the purpose of establishing a transparent and fair mobile distribution practice, became effective. The MDDIA limited the amount of subsidies a wireless 45 Table of Contents telecommunications service provider can provide to subscribers in order to prevent excessive competition among wireless telecommunications service providers. Pursuant to the MDDIA, wireless telecommunications service providers are prohibited from (i) unfairly providing discriminatory subsidies based on criteria such as type of subscription, subscription plan and characteristics of the subscriber and (ii) entering into a separate agreement with subscribers imposing obligations to use a specific subscription plan as a condition for providing subsidies. See “Item 5.A. Operating Results — Overview — Rate Regulations.” In addition, under the MDDIA, wireless telecommunications service providers were obliged to provide certain benefits, such as discounted rates, to subscribers who subscribe to their service without receiving subsidies. In June 2017, the State Affairs Planning Advisory Committee of Korea announced that it would encourage wireless telecommunications service providers, including us, to increase the applicable discount rate offered to subscribers from 20% to 25%, which we adopted in September 2017, and to offer additional discounts to low income customers, including those on government welfare programs and senior citizen recipients of the basic pension, which we implemented in December 2017 and July 2018, respectively. Although the MDDIA was repealed in July 2025, discounted rates offered under the MDDIA have been retained through a related amendment to the Telecommunications Business Act. We cannot provide assurance that we will not provide other rate discounts or lower-priced subscription plans in the future to comply with the Government’s public policy guidelines or suggestions. Interconnection Dominant network service providers such as ourselves that own essential infrastructure facilities or possess a certain market share are required to provide interconnection of their telecommunications network facilities to other service providers upon request. The MSIT sets and announces the standards for determining the scope, procedures, compensation and other terms and conditions of such provision, interconnection or co-use. We have entered into interconnection agreements with KT, LG U+ and other network service providers permitting these entities to interconnect with our network. We expect that we will be required to enter into additional agreements with new operators as the MSIT grants permits to additional telecommunications service providers. Frequency Allocation The MSIT has the discretion to allocate and adjust the frequency bandwidths for each type of service and may auction off the rights to certain frequency bandwidths. Upon allocation of new frequency bandwidths or adjustment of frequency bandwidths, the MSIT is required to give a public notice. The MSIT also regulates the frequency to be used by each radio station, including the transmission frequency used by equipment in our base stations. All of our frequency allocations are for a definite term. We pay fees to the MSIT for our frequency usage that are determined based upon our number of subscribers, frequency usage by our networks and other factors. For 2025, 2024 and 2023, the fee amounted to Won 99.8 billion, Won 103.0 billion and Won 102.5 billion, respectively. We currently use 10 MHz of bandwidth in the 2.1 GHz spectrum for our WCDMA services, 30 MHz of bandwidth in the 2.1 GHz spectrum, 20 MHz of bandwidth in the 800 MHz spectrum, 35 MHz of bandwidth in the 1.8 GHz spectrum and 60 MHz of bandwidth in the 2.6 GHz spectrum for our LTE services, as well as 100 MHz of bandwidth in the 3.5 GHz spectrum for our 5G services. In December 2022, citing the lack of progress made to date with respect to the implementation of 5G infrastructure for our use of the 28 GHz spectrum (800 MHz of bandwidth which was allocated to us in December 2018 for a period of five years until November 2023), the MSIT reduced the duration of our license for the use of such bandwidth by six months and asked us to install 15,000 base stations that use the 28 GHz spectrum by the end of May 2023, which we were not able to do within the Government’s requested timetable. Furthermore, in December 2022, the Government cancelled the allocations of bandwidth in the 28 GHz spectrum that had been provided to KT and LG U+, also citing the lack of progress made by these companies. In January 2024, the Government allocated 800 MHz of bandwidth in the 28 GHz spectrum to Stage X to provide nationwide wireless network services. However, in July 2024, the 46 Table of Contents Government revoked such allocation citing Stage X’s failure to meet the paid-in capital requirement and discrepancies in the actual ownership ratios of major shareholders and ownership structure compared to the information included in its frequency allocation application. For more information regarding the license fees for the various bandwidths that we use, see “Item 5.B. Liquidity and Capital Resources — Capital Requirements — Capital Expenditures” and note 16 of the notes to our consolidated financial statements. In December 2025, the MSIT announced plans to reallocate a total of 370 MHz of frequency bandwidths whose usage terms are due to expire in 2026 to KT, LG U+ and us, 155 MHz (in the 800 MHz, 1.8 GHz, 2.1 GHz and 2.6 GHz spectrums) of which will be allocated to us. We have applied for the renewal of the 20 MHz frequency bandwidth in the 800 MHz spectrum in December 2025, and we plan to apply for the renewal of the remaining 135 MHz of frequency bandwidths in June 2026. The final consideration to be paid by us for such reallocated bandwidths is expected to be conditional on the number of indoor 5G cell sites to be constructed by us by 2031. For risks relating to the maintenance of adequate bandwidth capacity, see “Item 3.D. Risk Factors — Risks Relating to Our Business — Our business, financial condition and results of operations may be adversely affected if we fail to acquire adequate additional frequency usage rights, renew existing frequency usage rights, or use our bandwidth efficiently to accommodate subscriber growth and subscriber usage.” Mandatory Contributions and Obligations All telecommunications service providers other than (i) value-added service providers and regional paging service providers or (ii) any telecommunications service providers whose net annual revenue is less than an amount determined by the MSIT (currently set at Won 30.0 billion) are required to provide “universal” telecommunications services including local telephone services, local public telephone services, telecommunications services for remote islands and wireless communication services for ships and discounted telephone services for handicapped and low-income citizens, or contribute toward the supply of such universal services. The MSIT designates universal services and the service provider who is required to provide each service. Currently, under the MSIT guidelines, we are required to offer a discount of between 35.0% to 50.0% of our monthly fee for wireless telecommunications services to handicapped and low-income citizens. In addition to such universal services for handicapped and low-income citizens, we are also required to make certain annual monetary contributions to compensate for other service providers’ costs for the universal services. The size of a service provider’s contribution is based on its net annual revenue for the previous year (calculated pursuant to the MSIT guidelines, which differ from our accounting practices). We recognized expenses relating to such contributions of Won 9.7 billion, Won 35.2 billion and Won 31.1 billion in 2025, 2024 and 2023, respectively. As a wireless telecommunications services provider, we are not considered a provider of universal telecommunications services and do not receive funds for providing universal service. Other network service providers that do provide universal services make all or a portion of their “contribution” in the form of expenses related to the universal services they provide. Foreign Ownership and Investment Restrictions and Requirements Because we are a network service provider, and the exception for the foreign shareholding limit under the Telecommunications Business Act does not apply to us, foreign governments, individuals, and entities (including Korean entities that are deemed foreigners, as discussed below) are prohibited from owning more than 49.0% of our voting stock. Korean entities whose largest shareholder is a foreign government or a foreigner (together with any of its related parties) that owns 15.0% or more of the outstanding voting stock of such Korean entities are also deemed foreigners. If this 49.0% ownership limitation is violated, certain of our foreign shareholders will not be permitted to exercise voting rights in excess of the limitation, and the MSIT may require other corrective action. Notwithstanding the above, pursuant to an amendment to the Telecommunications Business Act which became effective in April 2022, a Korean entity, so long as (i) such entity’s largest shareholder (determined by 47 Table of Contents aggregating the shareholdings of such shareholder and its related parties) is a foreign entity specifically designated by the MSIT incorporated in a country that has entered into a bilateral or multilateral free trade agreement with Korea, and (ii) such shareholder (together with the shareholdings of its related parties) owns 15.0% or more of the issued voting stock of such entity, may own more than 49.0% of our issued shares but may not exercise its voting rights with respect to the shares held in excess of the 49.0% ceiling until the end of the MSIT’s Public Interest Review. As of December 31, 2025, SK Inc. owned 65,668,397 shares of our common stock, or 30.6%, of our issued shares. As of December 31, 2025, the two largest foreign shareholders of SK Inc. each held a 3.4% stake therein. If such foreign shareholders increase their shareholdings in SK Inc. to 15% or more and any such foreign shareholder constitutes the largest shareholder of SK Inc., SK Inc. will be considered a foreign shareholder, and its shareholding in us would be included in the calculation of our aggregate foreign shareholding. If SK Inc.’s shareholding in us is included in the calculation of our aggregate foreign shareholding, then our aggregate foreign shareholding, assuming the foreign ownership level as of December 31, 2025 (which we believe was 36.2%), would exceed the 49.0% ceiling on foreign shareholding. If our aggregate foreign shareholding limit is exceeded, the MSIT may issue a corrective order to us, the breaching shareholder (including SK Inc. if the breach is caused by an increase in foreign ownership of SK Inc.) and the foreign shareholder which owns in the aggregate 15.0% or more of SK Inc. Furthermore, SK Inc. will be prohibited from exercising its voting rights with respect to the shares held in excess of the 49.0% ceiling, which may result in a change in control of us. In addition, the MSIT will be prohibited from granting us licenses or permits necessary for entering into new telecommunications businesses until our aggregate foreign shareholding is reduced to below 49.0%. If a corrective order is issued to us by the MSIT arising from the violation of the foregoing foreign ownership limit, and we do not comply within the prescribed period under such corrective order, the MSIT may: • revoke our business license; • suspend all or part of our business; or • if the suspension of business is deemed to result in significant inconvenience to our customers or to be detrimental to the public interest, impose a one-time administrative penalty of up to 3.0% of the average of our annual revenue for the preceding three fiscal years. Additionally, the Telecommunications Business Act also authorizes the MSIT to assess penalty surcharges of up to 0.3% of the purchase price of the shares for each day the corrective order is not complied with, as well as a prison term of up to three years or a penalty of Won 150 million. See “Item 3.D. Risk Factors — Risks Relating to Our Business — If SK Inc. causes us to breach the foreign ownership limitations on our common shares, we may experience a change of control.” We are required under the Foreign Exchange Transactions Act to file a report with a designated foreign exchange bank or with the MOFE, in connection with any issue of foreign currency denominated securities by us in foreign countries. Issuances of US$30 million or less require the filing of a report with a designated foreign exchange bank, and issuances that are over US$30 million in the aggregate within one year from the filing of a report with a designated foreign exchange bank require the filing of a report with the MOFE. The Telecommunications Business Act provides for the creation of a Public Interest Review Committee under the MSIT to review investments in or changes in the control of network service providers. The following events would be subject to review by the Public Interest Review Committee: • the acquisition by an entity (and its related parties) of 15.0% or more of the equity of a network service provider; • a change in the largest shareholder of a network service provider; 48 Table of Contents • agreements by a network service provider or its shareholders with foreign governments or parties regarding important business matters of such network service provider, such as the appointment of officers and directors and transfer of businesses; • a deemed foreigner (as discussed above) from a country whose government has entered into a bilateral or multilateral free trade agreement designated by the MSIT with the Government owning in excess of 49.0% of the outstanding voting stock of a network service provider; and • a change in control over a network service provider specified in the Enforcement Decree of the Telecommunications Business Act (including, but not limited to, the change of control over the holding company of such network service provider). If the Public Interest Review Committee determines that any of the foregoing transactions or events would be detrimental to the public interest, then the MSIT may issue orders to stop the transaction, amend any agreements, suspend voting rights, or divest the shares of the relevant network service provider. Additionally, if a dominant network service provider (which would currently include us and KT), together with its specially related persons (as defined under the Financial Investment Services and Capital Markets Act (the “FSCMA”)), holds more than 5.0% of the equity of another dominant network service provider, the voting rights on the shares held in excess of the 5.0% limit may not be exercised. Patents and Licensed Technology Access to the latest relevant technology is critical to our ability to offer the most advanced wireless telecommunications services and to design and manufacture competitive products. In addition to active internal and external research and development efforts as described in “Item 5.C. Research and Development, Patents and Licenses, etc.,” our success depends in part on our ability to obtain patents, licenses and other intellectual property rights covering our products. We own numerous patents and trademarks worldwide, and have applications for patents pending in many countries. Our patents are mainly related to wireless (LTE, 5G and Wi-Fi) technology, video codec, wireless Internet applications and AI. We are not currently involved in any material litigation regarding patent infringement. For a description of the risks associated with our reliance on intellectual property, see “Item 3.D. Risk Factors — Risks Relating to Our Business — Our business relies on technology developed by us, and our business will suffer if we are unable to protect our proprietary rights.” Seasonality of the Business Our business is not affected by seasonality. Item 4.C. Organizational Structure Organizational Structure We are a member of the SK Group, based on the definition of “group” under the Fair Trade Act. As of December 31, 2025, SK Group members owned in aggregate 30.6% of the shares of our issued common stock. The SK Group is a diversified group of companies incorporated in Korea with interests in, among other things, telecommunications, trading, energy, chemicals, engineering and leisure industries. Significant Subsidiaries For information regarding our subsidiaries, see note 1(2) of the notes to our consolidated financial statements. 49 Table of Contents Item 4.D. Property, Plants and Equipment The following table sets forth certain information concerning our principal properties as of December 31, 2025: Location Primary Use Approximate Area in Square Feet Seoul Metropolitan Area Corporate Headquarters 921,727 (1) Regional Headquarters 608,670 Customer Service Centers 107,277 Training Centers 344,966 Central Research and Development Center 319,789 Others(2) 2,452,391 Gyeongsang Provinces Regional Headquarters 491,706 Others(2) 1,267,236 Jeolla and Jeju Provinces Regional Headquarters 265,614 Others(2) 920,200 Chungcheong Province Regional Headquarters 565,761 Others(2) 950,674 (1) Represents our 93.25% ownership of SK T-Tower. (2) Includes base stations. Our registered office and corporate headquarters are located at SK T-Tower, 65, Eulji-ro, Jung-gu, Seoul 04539, Korea, which occupy a total land area of approximately 64,515 square feet. We own 93.25% of SK T-Tower, while the remaining 6.75% is owned by SK Square following the transfer of such interest to it by us pursuant to the Spin-off. In addition, we own or lease various locations for base stations and switching equipment. We do not anticipate that we will encounter material difficulties in meeting our future needs for any existing or prospective leased space for our base stations. See “Item 4.B. Business Overview — Cellular Services — Network Infrastructure.” We maintain a range of insurance policies to cover our assets and employees, including our directors and officers. We are insured against business interruption, fire, lightning, flooding, theft, vandalism, public liability and certain other risks that may affect our assets and employees. We believe that the types and amounts of our insurance coverage are in accordance with general business practices in Korea.