South Korea’s major telecommunications companies have suffered severe financial setbacks in Q3 2025 due to multiple data breach incidents, with combined operating profits dropping below ₩1 trillion for the first time in three quarters. The decline follows a series of major cybersecurity incidents that have affected the sector since early 2024.
The three major carriers – SK Telecom, KT, and LG Uplus – reported combined Q3 revenue of ₩14.73 trillion, showing a 1.7 percent year-on-year decrease. Their combined operating profit fell by 31.6 percent to ₩850.9 billion.
SK Telecom, which experienced its second major USIM data breach in three years, recorded the steepest decline, with Q3 revenue falling 12.96 percent year-on-year to ₩3.94 trillion and operating profit plummeting 91.8 percent to ₩43.7 billion. The company faces a ₩134.8 billion fine from the Personal Information Protection Commission following a universal subscriber identity module (USIM) data breach affecting approximately 27 million users. SK Telecom has offered a 50 percent discount on mobile service fees for affected customers and is expected to post a consolidated operating loss of ₩27.4 billion.
KT reported Q3 revenue of ₩6.87 trillion, up 3.3 percent year-on-year, with operating profit rising 15.16 percent to ₩534.5 billion. However, the company suffered a data breach exposing the international mobile subscriber identity of approximately 5,561 users, leading to confirmed losses of ₩240 million from unauthorized payments. The incident follows a previous security breach involving rogue femtocell devices that compromised its mobile payment systems. The Ministry of Science and ICT has referred KT’s case to police, citing the company’s lack of cooperation in investigations regarding unauthorized mobile payments.
The financial impact on SK Telecom includes regulatory fines and compensation payouts estimated at ₩1 trillion, along with customer losses from provider switching. KT’s ongoing investigation has uncovered additional illegal base stations linked to the unauthorized payment scheme, highlighting the sophisticated nature of the attacks targeting South Korea’s telecommunications infrastructure.
Industry analysts attribute the sector’s downturn primarily to one-off costs associated with the hacking incidents, fines, and customer compensation programs. “The telecommunications sector stands in stark contrast to other industries, such as semiconductors, which are reporting stronger earnings,” said KB Securities analyst Kim Ki-Hwan. The situation has prompted increased scrutiny of cybersecurity measures across the sector, with LG Uplus recently implementing new AI-powered security systems to prevent similar breaches.
Sources: Alpha Biz, Korea Times, Korea JoongAng Daily, Mobile World Live
