SK Telecom, South Korea's largest mobile carrier, reported a 12.5% year-on-year decline in net profit for the January–March 2025 quarter on Thursday, 7 May, as the company continued to absorb the financial and operational consequences of a massive cyberattack that struck its core servers in April last year. Net income came to 316.4 billion won (approximately US$218 million), down from 361.6 billion won in the same period a year ago, according to a regulatory filing cited by Yonhap News Agency.

Key Financial Results

Operating profit for the first quarter fell 5.3% on-year to 537.6 billion won, though the company noted this marked the first time quarterly operating profit has surpassed the 500 billion-won threshold since the large-scale cyberattack. Revenue slipped 1.4% to 4.39 trillion won. SK Telecom attributed the sequential recovery in operating profit to improved profitability in its artificial intelligence (AI) services segment, which partially offset the drag from the breach's aftermath.

Subscriber Recovery After Cyberattack

The cyberattack, which hit SK Telecom's main servers in April last year, triggered a significant customer exodus — the carrier reportedly lost around 600,000 mobile subscribers in the wake of the incident. The company has since launched aggressive recovery efforts, expanding membership benefits and increasing subsidies to win back and retain customers. Those efforts appear to be bearing fruit: SK Telecom added approximately 210,000 mobile subscribers in the first quarter of this year, signalling a gradual stabilisation of its subscriber base.

AI Business Driving Growth

Despite the broader revenue decline, SK Telecom's AI segment continued to expand at a rapid pace. Sales at its AI data centre business surged 89.3% on-year to 131.4 billion won in the January–March period. The company said it plans to strengthen its business-to-business (B2B) services through a comprehensive AI package covering infrastructure, models, and end-to-end services. It also reiterated its commitment to developing AI foundation models and deepening integration with global AI technologies to create synergies between its AI portfolio and core telecom operations.

Market Context: KOSPI Volatility

Separately, South Korean equities showed signs of profit-taking on Thursday morning after a record-breaking rally. The benchmark Korea Composite Stock Price Index (KOSPI) hit a new all-time intraday high of 7,523.84 shortly after the opening bell before retreating, adding 29.34 points, or 0.4%, to 7,413.9 as of 11:20 am local time. The index had surged 6.5% the previous session to breach the 7,000-point mark for the first time, closing at 7,384.56, amid rising optimism over a potential end to the US-Iran conflict. Traders moved to lock in gains following that record-breaking session.

What to Watch Next

The pace of subscriber recovery and the trajectory of SK Telecom's AI revenue will be closely watched in coming quarters. The company faces the dual challenge of rebuilding consumer trust after one of South Korea's most significant telecom data breaches while simultaneously positioning itself as an AI-first carrier in an increasingly competitive regional market. Analysts will look for clarity on the timeline and costs of any regulatory penalties or compensation obligations still pending from the cyberattack.