As competition in artificial intelligence (AI) technology among the three mobile carriers intensifies, SK Telecom led in R&D spending as a share of sales last year, followed by KT and LG Uplus. SK Telecom’s R&D spending fell in absolute terms, but its share of sales was the highest among the three. KT sharply increased R&D spending, narrowing the gap with SKT by a wide margin.

Data from the Financial Supervisory Service’s electronic disclosure system on May 6 showed R&D spending as a share of 2025 sales was 2.08 percent for SKT, 1.26 percent for KT and 0.95 percent for LG Uplus. From a year earlier, SKT fell 0.11 percentage point from 2.19 percent, while KT rose 0.46 percentage point from 0.80 percent. LG Uplus slipped 0.02 percentage point from 0.97 percent to 0.95 percent.

There was also a gap in absolute amounts. SKT spent 355.8 billion won on R&D last year, the most among the three. That was down 37.1 billion won from 392.8 billion won a year earlier, showing a downward trend.

KT increased R&D spending to 355.3 billion won in 2025 from 211.7 billion won in 2024, before deducting government subsidies, an increase of 143.6 billion won. That represents a 68 percent rise. Annual R&D spending, which had remained in the 200 billion won range for several years, jumped to the mid-300 billion won range. The R&D spending gap with SKT, which exceeded 180 billion won in 2024, narrowed to about 500 million won.

LG Uplus spent 147.9 billion won on R&D last year, before deducting government subsidies. That was up 5.3 billion won from 142.6 billion won a year earlier. R&D spending rose slightly, but its share of sales fell, making it the only one of the three below 1 percent.

Each company focused its R&D capabilities on AI and network upgrades. SKT cited key achievements including improving resource efficiency at AI data centers (AIDC), enhancing and commercialising its in-house language model A.Dot X (A.X), and developing AI content conversion and generation technologies. On infrastructure, it worked on improving 5G standalone (SA) performance and developing positioning-based technologies and platforms.

KT cited key achievements including development of its Korean-language independent large language model (LLM) "Mi:deum 2.0" and commercialisation of an AI-based real-time voice phishing detection engine. In agentic AI, it pursued development of an AI semiconductor-based LLM inference solution and development of Llama K and SOTA K based on global open-source models. It also succeeded in linking 5G commercial base stations with multi-vendor open RAN radio equipment, and carried out joint research cooperation with Samsung Electronics on next-generation 6G communications.

LG Uplus invested its R&D capabilities in upgrading AI services centred on ixi-O. In the fourth quarter last year, it developed technology to call and respond to an AI agent during ixi-O calls, and developed an engine that infers detailed reasons for complaint calls to customer service centres. In the third quarter, it also developed technology that analyses call histories with AI to link voice phishing risk levels to financial services. Even as it sought to expand AI services, its R&D spending as a share of sales remained the only one of the three below 1 percent.

Accounting treatment for R&D costs also differed. R&D costs are typically treated as selling and administrative expenses during the research stage, but are recognised as intangible assets when technical feasibility, commercial viability and future economic benefits can be demonstrated.

KT recognised 143.7 billion won, about 40.5 percent of its total R&D costs last year, as intangible assets. That was up 124.8 billion won from 18.9 billion won in 2024. SKT recognised 16.9 billion won, about 4.8 percent of its R&D costs, as intangible assets. LG Uplus treated all R&D costs as selling and administrative expenses.

SKT and LG Uplus will report results for the first quarter of 2026 on May 7. FnGuide forecast SKT’s first-quarter consolidated operating profit at 512.7 billion won, about 9.6 percent lower than a year earlier. Over the same period, LG Uplus operating profit is expected to rise about 10.1 percent to 281.2 billion won.

KT will report first-quarter results on May 12. KT’s operating profit for the first quarter this year is forecast at 505.3 billion won, down 26.6 percent from a year earlier.