Lawsuit Begins Over 96.3 Billion Won Collusion Fine for Three Major Mobile Carriers

First Hearing for KT's Lawsuit to Overturn KFTC Order Set for January 15
"Agreement on Number Portability Unlikely to Have Been Established"

The administrative lawsuit regarding number portability collusion between the three major mobile carriers-SK Telecom, KT, and LG Uplus-and the Korea Fair Trade Commission (KFTC) is set to begin in earnest at the start of the new year. The KFTC imposed a total fine of approximately 96.3 billion won, arguing that the agreement to prevent imbalances in the net increase or decrease of number portability subscribers constituted collusion. However, the telecom companies are pushing back, claiming that such an agreement is difficult to establish in the first place.

Logos of the three major mobile carriers. Photo by Yonhap News

The 7th Administrative Division of the Seoul High Court (Presiding Judge Koo Hoegeun) will hold the first hearing for KT’s lawsuit to cancel the corrective order issued by the KFTC (case number 2025Nu7552) on January 15. The hearing schedules for the lawsuits between the KFTC and SK Telecom (2025Nu8223), as well as LG Uplus (2025Nu8220), have not yet been set.

The three mobile carriers have hired major law firms to counter the KFTC. KT is represented by Bae, Kim & Lee LLC, with Song Woochul (16th Judicial Research and Training Institute), former Chief Research Judge at the Supreme Court, among the legal team. SK Telecom is represented by Kim & Chang, while LG Uplus has entrusted the case to Lee & Ko and HwaWoo. Veteran corporate lawyers such as Oh Geumseok (18th class) from HwaWoo, Sung Changho (25th class) from Lee & Ko, and Kim Bongseon (31st class) from Kim & Chang have joined the defense teams.

In March 2025, the KFTC announced sanctions against the three mobile carriers for colluding to adjust the number of number portability subscribers, imposing a provisional fine of approximately 114 billion won. During the KFTC’s decision process, the fine was adjusted to about 96.3 billion won: SK Telecom was fined approximately 38.8 billion won, KT 29.9 billion won, and LG Uplus 27.6 billion won.

According to the KFTC, after being sanctioned by the Korea Communications Commission in December 2014 for excessive sales incentives, the three mobile carriers operated a situation room with the Korea Association for ICT Promotion (KAIT) as a form of self-regulation. The carriers shared information on their number portability status and sales incentive levels in this situation room, and by around November 2015, they were found to have colluded. The agreement aimed to prevent the net increase or decrease in number portability subscribers from being concentrated with any one carrier. Until the end of September 2022, when the situation room was disbanded, the carriers would adjust the number of net increases or decreases for each company by increasing or reducing sales incentives through mutual consultation whenever the figures became skewed toward a particular carrier.

The KFTC stated, "Records of KAIT employees' work confirmed the maintenance and execution of collusion among the three mobile carriers," and added, "Before the collusion in 2014, the three carriers had a daily average net change of 3,000 number portability subscribers, but after the collusion in 2016, this dropped to around 200." The KFTC further explained, "The total daily number of number portability cases also decreased from about 28,800 in 2014 to 15,600 in 2016, and to around 7,200 in 2022." The three carriers argued, "It is difficult for three fierce competitors to reach any agreement, and there is no incentive to do so."

In its decision, the KFTC stated, "This agreement did not limit the net increase or decrease in number portability subscribers to a specific level, but was rather a loose agreement to prevent imbalances in the net changes." The commission added, "The three carriers refrained from full-scale competition, but in situations such as the college entrance exam period or the launch of new devices, which are opportunities to attract customers, they acted contrary to the agreement to maximize profits." The KFTC continued, "Since the mobile telecommunications market is saturated, the only way for the three carriers to increase subscribers is to compete over number portability. This inevitably creates a 'chicken game' dynamic, providing an incentive for the carriers to agree to restrain competition over attracting number portability subscribers."

Lee Sangwoo, Legal Times Reporter

※This article is based on content supplied by Law Times.