Subscriber exodus continues for SK Telecom after mass data leak

Close to a million users switched carriers in May, but SKT still leading the market

The notifications posted outside of an SK Telecom store in Seoul on May 14 alert users of the information protective measures that are being provided, after the mass data breach via hacking attack that was publicized in April. (Yonhap)

Korea's largest mobile operator SK Telecom, which revealed in April that it had been subject to a massive data breach, continued to lose subscribers in May as more chose to switch to other operators.

According to Korea Telecommunications Operations Association data released Monday, 677,491 people ended their subscriptions with SKT in April and May. The company added 157,631 new members in the same period, meaning it suffered a net loss of over 500,000 subscribers over the two months.

Most customers who stopped using SKT's wireless services have opted for its two main rivals, KT and LG Uplus, who were No. 2 and No. 3, respectively, in the market according to April data by the Ministry of Science and ICT. Some 292,638 of the former SKT users went to KT, while 244,630 are now using LG's services.

In total, 943,509 people switched their mobile operators in May, up drastically from 525,937 in March and even 690,954 in April, when SKT first shared news of the mass data breach via hacking attack with the public. The monthly figure has rarely surpassed 600,000 in the past.

SKT is likely to remain the top mobile operator for the time being, with Science Ministry data showing that the company had a 40.25 percent market share in the first quarter of this year. However, if the recent numbers are taken into account, SKT's market share could drop below the 40 percent mark. Though this would still place the company well ahead of its rivals, its lead would be considerably smaller.

The yearslong hacking attack on SK Telecom's systems is thought to have resulted in the theft of 9.82 gigabytes of sensitive SIM-related data related to well over 20 million users. SK Group Chairman Chey Tae-won issued a public apology earlier last month, 19 days after one of the largest cyberattacks in the country's history was revealed.