Whatever neighborhood you happen to be in, three mobile phone shops always stand within sight of one another, more or less in a row. One red sign, a sign of a different color beside it, and a third a little way off. Only the colors differ; what they sell inside is nearly identical. Even the price plans resemble one another to an uncanny degree. When one shop raises its rates a little, the other two quietly follow; when one puts out a new plan, two similar ones appear within a few weeks. Did they collude on this, you want to ask. But colluding openly is against the law. Moving as if in collusion without ever actually colluding — that is what these three companies have been doing for a very long time.
In the last three stories I wrote about walls that a single company held alone. Today's wall is a little different. This wall was built not by one company but by three, raising it together while facing one another. Economics has a name for this: oligopoly. A handful of players divide a market among themselves and take care never to disturb the lines of the division. SK Telecom, KT, and LG Uplus. This is the story of the three mobile carriers we pay our bills to every month.
An Old Triangle Called Five to Three to Two
For a long time, the ratio by which these three companies divided the market was roughly five to three to two. SK Telecom takes half, KT one in three, LG Uplus the rest. The ratio has stayed unchanged for a surprisingly long time. The picture from ten years ago and the picture from last year lie almost perfectly on top of each other. There are reasons a market can sit this still.
First, no one new can get in. Blanketing the country with base stations and buying up spectrum costs astronomical amounts of money. Over the past dozen or so years there have been several attempts to launch a fourth carrier, and every one of them failed at the threshold and disappeared. The wall was so high that a fourth was never even born. Second, those of us inside rarely move either. Switching carriers is somehow a bother. There is a contract, there is a penalty, and the number portability paperwork is tedious. So most people stay with the same company for ten years, twenty years. I am one of them.
| Company (2025, consolidated) | Revenue | Operating profit | 2025 in one line |
|---|
| SK Telecom | 17.0992 trillion won | 1.0732 trillion won | Hacking incident breaks the 40% line |
| KT | 28.2442 trillion won | 2.4691 trillion won | No. 1 in revenue on non-telecom and real estate |
| LG Uplus | 15.4517 trillion won | 892.1 billion won | The only one growing |
| Three combined | 60.9555 trillion won | 4.6389 trillion won | — |
In 2025, the three companies' revenues added up to more than 60 trillion won, and their operating profit came to 4.6 trillion. The interesting part is that the revenue leader is not SK Telecom but KT. Twenty-eight trillion won. But this is not money earned from mobile service. KT is a company that carries landline phones and internet, real estate, even a card business, and much of its bulk comes from beyond telecom. Looking purely at the market that fits in the palm of a hand, the one standing at the front is still SK Telecom. Or, to be precise, it was — until the spring of 2025.
The Year the Balance Shook
In April 2025, word got out that the USIM cards holding SK Telecom subscribers' data had been hacked. For a carrier, few kinds of accident are more fatal. What people entrust to a carrier is, in the end, a single thing — trust — and a hole had been punched through the very middle of it. The government ruled the incident the company's fault and told it to waive the shackle that had long held people in place, namely the early termination penalty. SK Telecom accepted.
Here the second reason I mentioned gets turned on its head. People rarely switched carriers largely because switching was a bother and the penalty was frightening. When the penalty disappeared, the locked door swung open for a moment. And people began slipping out through it. After the breach became known, the number of people who left SK Telecom reached 600,000. In the six days after the penalty waiver was announced, 75,000 packed their bags. The 40% share that had never once given way sank below the line for the first time.
The amusing part is what came next. The 600,000 who left SK Telecom did not evaporate; most of them walked straight into the two houses next door. KT and LG Uplus did nothing particularly remarkable. They simply stood in front of the door while it was open. And from that spot they quietly gathered up the fruit. In 2025, while SK Telecom staggered — spending on the order of a trillion won on hacking compensation and even lowering its revenue forecast — the results at KT and LG Uplus rebounded side by side. That is how the triangle of oligopoly is built. When one vertex trembles, the weight does not disappear; it shifts onto the other two.
Inside the Wall, Everyone Builds a Room Next Door
So will these three companies stay comfortable inside this triangle forever. Not necessarily. Because the main house itself — telecom — is a house that no longer grows.
Almost no one in this country goes without a mobile phone now. As with KakaoTalk, there are no new customers left for mobile service to bring in. And rates are an item that politics and public opinion keep under permanent watch, so raising them at will is difficult. So the three companies, as if by appointment, began looking in the same direction. Outside telecom. KT turns toward real estate, cards, and artificial intelligence; LG Uplus toward data centers and non-telecom businesses; SK Telecom toward AI. It is exactly what Kakao and Naver did in the last story, building new rooms on top of the main house of messaging and search. Inside a wall that has finished growing, the only thing left to do is put in another room next door.
The wall of an oligopoly is a curious object. A wall built by one company need only be defended by that one company; a wall built by three is barely held up, the three of them watching one another out of the corners of their eyes. From the outside it looks like the most placid equilibrium in the world. No one lowers rates first, and no one picks a fight first. But that calm holds only while all three vertices stand in place. As SK Telecom showed in 2025, the moment one of them stumbles, the quiet triangle tilts more easily than you would think. And whether that equilibrium was ever really for the consumer — the fact that 600,000 people walked out without hesitation the moment the door briefly opened seems to answer that, faintly.
The Same Oligopoly, Different Timetables
The oligopoly these three companies share shows up just as plainly in their employees' timetables.
| Company | Employees | Average annual pay | Average tenure | Revenue per employee | Operating profit per employee |
|---|
| SK Telecom | 5,316 | approx. 163 million won | 13.7 years | approx. 3.22 billion won | approx. 200 million won |
| KT | 14,701 | approx. 118 million won | 19.3 years | approx. 1.92 billion won | approx. 170 million won |
| LG Uplus | 9,765 | approx. 117 million won | 11.3 years | approx. 1.58 billion won | approx. 91 million won |
All three pay more than 100 million won a year, but tenure runs from one extreme to the other. KT, which began life as a state enterprise, once averaged 22 years; after the spin-off of its network division and a round of voluntary redundancies in 2025, headcount fell from 19,727 to 14,701, and tenure came down to 19.3 years. Even the timetable inside the wall could not escape restructuring. Still, with Kakao at six-odd years, that is three times as long. The latecomer LG Uplus, meanwhile, sits at eleven-odd years. Even inside the same triangle, when the roots differ, so does the length of time people stay. The older the wall, the longer the people inside it remain.
The next story concerns the last wall. The walls so far were raised by law, by nature, by habit, or by the tacit equilibrium of a few. The last wall is different. A wall built by the force of technology and cost alone, one that only a handful of places in the world can climb. The pillar of our exports, standing these days at the very center of the age of artificial intelligence: the memory semiconductor story of Samsung Electronics and SK hynix.
This piece is part of the "Korea Value Chain" series and is an original work. It is an analysis based on public data and industry sources; some figures and assessments are estimates. It is not intended as a direct basis for investment decisions.
By Alexandro Lee · July 2026
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