Seoul, July 18, 2025 – SK Telecom, a long-standing powerhouse in South Korea's mobile telecommunications market, has been hit by a shocking turn of events, with its market share plummeting below the 40% mark due to the aftermath of its worst-ever hacking incident. Following the massive personal data breach in April, a sharp exodus of subscribers has materialized, and the prevailing forecast is that the domestic mobile telecommunications market landscape will accelerate its transformation.

According to statistics on wireless and wired communication service subscriptions and wireless data traffic for May, released today (18th) by the Ministry of Science and ICT, SK Telecom's mobile subscriber count as of May was 22,499,042, accounting for 39.29% of all mobile subscribers. This represents a decline of approximately 425,000 subscribers and a 0.79 percentage point drop in market share compared to April, when it barely maintained the 40% level with 22,924,260 subscribers (40.08%). This is the first time SK Telecom's mobile market share has fallen below 40%, and it is expected to be recorded as a symbolic indicator of SK Telecom's historical crisis.

This decline in market share is directly linked to the hacking incident that occurred in April. At that time, SK Telecom experienced an unprecedented breach where personal information of approximately 600,000 customers was leaked. The leaked information included sensitive personal details such as names, phone numbers, and birth dates, causing extreme anxiety among customers. Immediately after the incident, SK Telecom CEO Yoo Young-sang issued a public apology, promising to prevent recurrence and announcing plans for customer compensation. However, customer trust had already been severely damaged. The severity of the situation is further highlighted by the fact that the exodus continued despite SK Telecom's drastic measure of waiving early termination fees for number portability subscribers from early this month until the 14th. In fact, over 600,000 customers have already left SK Telecom since the April hacking incident.

The subscriber exodus from SK Telecom has resulted in a windfall for its competitors, KT, LG Uplus, and the MVNO (Mobile Virtual Network Operator) businesses. KT secured 13,610,780 subscribers (23.77%) as of May, seeing its market share increase by 0.32 percentage points in just one month. LG Uplus also showed consistent growth, rising by 0.23 percentage points to 11,131,466 subscribers (19.45%). The surge in the MVNO market is particularly notable. In May, MVNO subscribers totaled 9,997,971, an increase of 135,997 from April, accounting for 17.47% of the total. This demonstrates that MVNOs are emerging as attractive alternatives for customers seeking reasonable consumption based on affordable plans. There is growing weight to the analysis that the proportion of MVNOs will continue to expand in a market structure traditionally dominated by the three major telcos.

Industry experts believe that SK Telecom's decline in market share is likely to continue for some time. This is because significant time will be required to repair the damage to the company's image and restore customer trust caused by the hacking incident. Furthermore, the May statistics predate SK Telecom's implementation of the early termination fee waiver policy, meaning that the June statistics, to be released later this month, are likely to show an even lower market share for SK Telecom. Although SK Telecom is preparing various customer retention incentives in addition to the fee waiver, some assessments indicate that these efforts may be insufficient to bring back customers who have already decided to leave.

This incident is not merely a decline in market share for SK Telecom; it raises fundamental questions about the company's crisis management capabilities and its overall security system. While various companies have experienced hacking incidents in the past, SK Telecom's case is particularly impactful due to its dominant position in the domestic telecommunications market. SK Telecom must make thorough efforts to restore lost customer trust and completely overhaul its security system to prevent similar incidents from recurring.

Meanwhile, regarding this hacking incident, the police are investigating Mr. C on charges including violation of the Child Welfare Act. It is urgent to clarify the exact motives and mastermmind behind the hacking, as well as to establish legal and institutional safeguards to prevent recurrence. This SK Telecom hacking incident is expected to serve as another wake-up call for domestic companies regarding the importance of information security. Competition in the telecommunications market will intensify, and each operator has learned the lesson of having to adhere to the most fundamental value of protecting customer information, beyond merely competing on service quality.