Samsung & SK Hynix: Inside the Kospi Mania

"Modern capitalism is a pro at two things: generating wealth and generating envy."

– Morgan Housel, The Psychology of Money, 2020

Kospi.

South Korea’s main equity index.

And, at the moment, the name of the game. Why? Because no market on Earth is making — and losing — money faster, louder and more emotionally than this one.

But first, the country. South Korea is one of the great economic miracles of the last century. A nation of 52 million people that went from post-war poverty to top-10 industrial powerhouse within two generations. You know its exports even if you have never landed in Seoul: Hyundai and Kia on your roads, LG in your kitchen, K-pop in your kids’ headphones — and a Samsung device probably within one meter of you right now.

And, full confession: I love Korean barbecue. Everything happens over an open flame, right in front of you. The heat is immediate, the sizzle is loud, and the line between perfectly seared and burnt is measured in seconds.

Keep that flame in mind. It will carry us through the next four minutes.

Now, we Swiss love to complain that our own index is concentrated. Three elephants — Nestlé, Novartis and Roche — make up roughly half of the SMI, and every finance textbook in Zurich uses us as the cautionary tale.

You think that’s concentrated?

Check South Korea.

In 2016, one conglomerate and one memory chipmaker together accounted for about 16% of the Kospi. Today, the two of them make up more than 54%! Yes, fifty-four percent! More than half of a nation’s stock market (chart 1).

How does that happen? How does an old, boring, brutally cyclical commodity industry swallow an entire index?

Enter Samsung Electronics.

And SK Hynix.

Chart 1: Samsung and SK Hynix weight in the Kospi — from 16% to more than half the index, 2016–2026

Samsung & SK Hynix: A Gift and a Curse

If you read our Weekly on Apple vs Micron, you already know the plot: memory chips — DRAM and NAND — were the unloved commodity corner of technology. Then AI arrived and needed one thing above everything else: memory.

Enormous, unprecedented amounts of it.

Samsung Electronics is the conglomerate you think you know. Yes, it builds your phone, your TV, maybe your fridge. But the real engine sits deeper: smartphones and semiconductors deliver over 70% of both revenue and profit — and right now, the memory division is carrying the show almost alone.

SK Hynix is the Pure-Play. DRAM, NAND, and above all High Bandwidth Memory — the premium chips stacked next to Nvidia’s AI processors. SK Hynix leads that market and became the quiet arms dealer of the AI race.

The results are historic. Since the launch of ChatGPT in November 2022, SK Hynix is up more than 2,000%. Samsung more than 300% (you see the pure play edge of SK Hynix…). And the Kospi doubled in roughly one year — after needing the previous two decades for its last double.

A “Good Story”? Undeniably.

But this success is a gift and a curse at the same time.

Because when two stocks are half the index, the index inherits their mood swings. The Kospi has been halted seven times this year. One halt lasted 20 minutes after the index — the entire index — dropped 8% in a single session (chart 2). Daily swings of plus or minus 10%, in a national benchmark. For two decades, a 3% move was a rare event. Suddenly, it’s a Tuesday.

And the whole country is watching. In cafés, in taxis, in office elevators: Samsung and SK Hynix are the national conversation. Pension money rides the very same rollercoaster.

Charlie Munger once described the Korean mentality: "Koreans came up from nothing in the auto business. They worked 84 hours a week with no overtime for more than a decade. At the same time every Korean child came home from grade school and worked with a tutor for four full hours. Are you surprised when you lose to people like that? Only if you’re a total idiot."

That intensity built the miracle. Now the very same intensity has turned to the stock market.

Fun Fact:South Korea counts 102 million active trading accounts. The country has 52 million inhabitants. Statistically, every Korean — every newborn included — holds two.

So, what does sudden wealth do to human beings?

Chart 2: The Kospi and its one-day percentage changes — two decades of calm, then chaos, 2006–2026

Cartier, Rolex, Tesla: The Goalpost Starts Moving

Here is where the story stops being about chips and starts being about us.

A Samsung memory worker with a base salary of around $52,000 is expected to receive a total bonus of roughly $410,000 this year. At SK Hynix, bonuses are expected to top $454,000. Measured against the average Korean salary, that is roughly a decade of income — landing in one single payout.

What happens next is as old as money itself.

Luxury jewelry sales in South Korea: up 146% year over year. Luxury watches: up 85%. Cartier boutiques with waiting lists, Rolex dealers sold out, Tesla registrations surging — imported car registrations jumped over 40% in four months (chart 3).

Psychologists call it lifestyle inflation.

The bonus arrives, the goalpost moves, and yesterday’s dream becomes today’s baseline. We covered the pattern in our book club on the Psychology of Money: human nature never changes — only the ticker symbols do. Wealth on one side. Envy on the other. Human emotions at their finest.

And it doesn’t stop at spending. It spills into how people invest.

South Koreans are liquidating savings and surrendering insurance policies to buy stocks. Margin loans hit a record 36 trillion won (around 26 billion dollars) this year — double the level of a year ago. When brokerages raised margin rates toward 10%, retail investors didn't slow down. They moved to bank credit lines instead. One civil servant posted his brokerage account online: 2.3 billion won (about 1.7 million dollars) entirely in SK Hynix, 1.7 billion of it (about 1.3 million dollars) borrowed.

That is not investing. That is FOMO (Fear Of Missing Out) wearing a suit.

To be crystal clear where we stand at arvy: we would never advise this. Sleep a night over every big financial decision. Ask yourself first whether you truly need the thing — or the position. And yes, enjoy your money too; we are the ones quoting Die With Zero and its memory dividends at our book club. Balance is the point. Betting borrowed money on one single stock is not balance.

It’s holding your hand ever closer to the open flame.

So, what does the “Good Chart” say?

Chart 3: Luxury sales and imported car registrations explode as the Kospi triples

Samsung & SK Hynix Stock Price: Wide, Loose and Vertical

Let’s be precise, because this is where a “Good Story” and a “Good Chart” part ways.

The story is real. The earnings are real. Memory prices are locked into multi-year agreements, and the AI buildout is not fiction. Wonderful businesses, without question.

But a wonderful business is not automatically a wonderful investment. Especially not at any price. And especially not at this stage of the chart (chart 4).

In our three-part series, the Semiconductor Climax Run, we described exactly the pattern now unfolding: wide and loose price action after a vertical run. It is the signature of every late-stage top in market history.

The mechanism is simple. Early in a trend, strong hands accumulate quietly — tight action, steady progress. In the climax phase, the stock changes hands violently: euphoric latecomers buy from exiting insiders, and the swings explode in both directions.

The tell is the combination: maximum volatility, minimum progress. When an index swings close to 10% a day but goes nowhere for weeks, distribution is doing its work in plain sight. Volatility clusters at two places — bottoms and tops.

Nobody confuses this one for a bottom.

We are not crash prophets. Nobody rings a bell at the top, and parabolas can run further than any rational mind expects. But a framework beats a feeling: respect the line of least resistance, sell into strength in tranches, and never let one position — or one loan — decide your financial life. With the Bank of Korea expected to raise rates, every borrowed won in this market is about to get more expensive.

Back at the barbecue, the best grill masters share one skill: they pull the meat off the flame just before it’s done.

Not after. And they have a framework, just like the one we use in our semiconductor trilogy.

Because the flame never tells you when the right moment has come.

And neither does the Kospi.

Chart 4: Samsung, SK Hynix and the Kospi since the launch of ChatGPT, November 30, 2022