Part 5 · Exchange rates and exports: the key to the Korean market · Lesson 26
Exports are the heart of the Korean stock market
A large share of Korean companies' profits comes from across the sea. That is why the stock market listens when the export report card comes out on the 1st of every month.
QToday's question
Why does the stock market listen to the 'monthly trade statistics' released on the morning of the 1st of each month?
On October 1, 2026, the Ministry of Trade and Industry announced that September exports were $120.9 billion, up 83.5% from a year earlier. Semiconductors accounted for nearly half of that, at $60.3 billion. Because a large share of Korean companies' profits comes from goods sold abroad, this number acts as a report card that previews upcoming corporate earnings. In this lesson we look at how to read this report card and how closely exports and KOSPI have actually moved together.
MAPLearning map for this lesson
We build it up in three steps. At the end of each step, a 'Quick check' lets you test your understanding before moving on.
In Lesson 2 you learned that Korea's exports exceed 41% of GDP and semiconductors make up about 20% of exports, and in Lesson 3 the cycle in which memory chip prices swing widely. In Lesson 4 you saw that net exports are one piece of GDP, and in the previous Lesson 25 that exchange rates shake exporters' won-denominated profits. This lesson connects those pieces into one line: 'exports → earnings → stock prices'.
- STEP 1 · Basic conceptsHow to read the export report card
You will be able to tell what the total, growth rate, , items and in the each mean.
- STEP 2 · Understanding the principleHow exports lead to stock prices
You will be able to split export value into price and volume, and explain how rising exports lead to stock prices through the earnings knob, along with its pitfalls (base effect and concentration).
- STEP 3 · Real-world applicationTen years of exports and KOSPI
You will be able to check with real data how closely export growth and KOSPI returns moved together and 'who moves first', and set up the order for reading release day.
STEP 1How to read the export report card
Exports are the biggest number among Korean economic indicators to come out the fastest. The previous month's results are published as soon as the month turns, so it becomes the first report card the market checks.
An easy analogy · A shop's month-end sales ledger
Imagine the biggest shop in the neighborhood posts last month's sales ledger on its door every morning on the 1st. The merchants around it read that ledger and are the first to notice 'business has picked up lately' or 'that item is selling well'. In Korea, exports play the role of that big shop. When the export ledger is good, expectations rise among suppliers, employees and even investors.
The 1st of every month: trade statistics
On the morning of the 1st of every month, the Ministry of Trade and Industry (formerly the Ministry of Trade, Industry and Energy) releases the previous month's based on Korea Customs Service clearance data. Unlike indicators such as GDP that come out long after a quarter ends, it is the 'fastest big indicator', released as soon as the month turns. So in Korea, where carry a large weight, this release is the first clue to reading that month's economic flow.
Using the September report card released on October 1, 2026 as an example, let's read five numbers in turn.
Source: Ministry of Trade and Industry, 'September 2026 trade statistics' (Oct 1, 2026). Checked 2026-10-05.
Why look at both the growth rate and the daily average?
Exports are usually released as a growth rate. Export volume varies by season, so comparing with the same month a year earlier is fairer than comparing with the previous month. But even in the same September, the days that factories and ports worked, that is, the number of working days, can differ because of holidays. In September 2026, the Chuseok holiday meant fewer working days than a year earlier. So the growth rate of , divided by working days (+105%), came out higher than the growth rate of the total (+83.5%). The total grew a lot even with fewer working days, which means the actual momentum was stronger.
The trade balance is 'how much was left over'
Exports minus imports is the . A large surplus tends to bring in lots of dollars and support the won (Lesson 24). But you have to look at the 'reason' for the surplus. A surplus created by growing exports and a so-called 'recession-type surplus' created by shrinking imports of raw materials and parts because the economy is bad mean the exact opposite things, even though both are surpluses.
Quick checkOne month's total exports fell 2% from a year earlier, but daily average exports rose 6%. How should we read the momentum of exports that month?
STEP 2How exports lead to stock prices
Now that you can read the report card, let's follow the path by which this number reaches stock prices. The 'earnings knob' from Lesson 1 shows up again here.
Export value = price × volume
Even for the same 'export increase', corporate profit and its staying power differ depending on whether the growth came from selling at higher prices or selling more. Exports lifted by price raise margins sharply, but can reverse quickly when the cycle turns.
Four steps from exports to stock prices
Export value ↑
Overseas sales grow through higher prices or higher volume.Won revenue ↑
Dollar revenue becomes won revenue. The exchange rate enlarges or shrinks it (Lesson 25).Operating profit ↑↑
Fixed costs stay the same, so profit grows by more than revenue (Lesson 3).EPS and stock price ↑
When profit per share grows, the stock price's earnings knob turns up (Lesson 1).The third step is especially important. Fixed costs such as factories and staff don't rise much when exports grow, so when revenue grows 20%, profit can grow far more. This is why, in Lesson 3, profit swung by multiples when memory chip exports moved ±30%.
See it in a chart: what was sold to reach $120 billion?
Tap a bar to see each item's value, growth rate and related sectors. Switch between the full year 2025 and the single month of September 2026 and compare how the semiconductor share changed.
2025 exports of $709.7 billion, share by item
Sources: Ministry of Trade and Industry, '2025 annual trade statistics' (Jan 1, 2026, Korea Policy Briefing) and 'September 2026 trade statistics' (Oct 1, 2026). September 2026 item values are the press release's figures rounded to $100 million; 'Other' is the total minus the listed items. Checked 2026-10-05.
In 2025 too, semiconductors were the No. 1 item at $173.4 billion, 24.4% of exports. Their share grew from 2024 ($141.9 billion, about 21%). In September 2026, a single month of semiconductor exports at $60.3 billion became about 50% of the total. A large part of this surge is price. According to the same press release, the DRAM contract price (DDR5 16Gb) rose 687.5% from a year earlier to $48.00 in September. The supply-and-demand price cycle seen in Lesson 3 pushed up the whole export number. Exports excluding semiconductors grew 23%.
Common misconceptions
- "The higher the export growth rate, the better the signal, no matter what?"
- If exports were unusually weak a year earlier, even a small recovery produces a big growth rate. This is the you learned in Lesson 8. You also need to look at the level of the value itself, the daily average, and items other than semiconductors.
- "When exports improve, export stocks rise from that day?"
- The market moves in advance, anticipating that exports will improve (pricing in, Lesson 20). In fact, as you'll see in STEP 3, KOSPI has tended to move several months before exports. On release day, whether it was good 'relative to forecast' matters more.
- "If exports hit a record high, are all export sectors doing well?"
- Even in September 2026, autos (−5%), displays (−9%) and biohealth (−9%) fell. A single item can lift the total, so you have to break it down by item to see your own sector's results.
Quick checkSemiconductor exports doubled in a year, but export volume was almost unchanged. What mainly caused the increase? And what should you watch out for?
STEP 3Ten years of exports and KOSPI
Now let's check with data whether exports and stock prices really moved together. And find out for yourself which of the two moved first by sliding the lines.
Overlaying the two lines
The chart below overlays the monthly export growth rate (versus the same month a year earlier) and KOSPI's one-year return since 2015. Use the slider to push the KOSPI line back by a few months and check whether KOSPI moved before exports.
Export growth vs. KOSPI one-year return (Jan 2015 – Aug 2026, monthly)
Move over the chart to see that month's two numbers.
Sources: Bank of Korea Economic Statistics System (ECOS) 403Y001 export value index (total), year-over-year change; Naver Finance KOSPI month-end close, one-year return. Correlation coefficient calculated by Robin Invest. Checked 2026-10-05.
The same-month correlation coefficient over the full period is 0.72. The closer to 1, the more they moved together, so it is a fairly solid relationship. During the 2017 semiconductor boom exports grew 10–30% and KOSPI rose around 20%, and in 2019 both were negative together. In 2026, with semiconductor prices surging, export growth was in the 70% range and KOSPI's one-year return was well over 100%.
Slide the slider and a more interesting fact appears. When KOSPI is placed 3–4 months ahead, the correlation coefficient rises to 0.83–0.85. Even leaving out the extreme numbers of 2026 and looking only through June 2025, it rises from 0.52 to 0.72–0.74. This means stock prices moved several months before exports. As you learned in Lesson 6, stock prices are a leading indicator themselves, and the market prices in improving exports ahead of time. The export number on the 1st of each month is often a report card confirming 'what stock prices had already guessed'.
There are years they didn't walk together
In March 2022 exports grew 21.6% from a year earlier, but KOSPI's one-year return was −9.9%, and in June the gap widened further, with exports +7.1% and KOSPI −29.2%. That year the US and Korea raised rates quickly and the 'multiple knob' of Lesson 1 fell sharply (Lesson 17). It shows that exports move only the earnings knob, while the multiple knob is held by interest rates and sentiment.
Concentration is both an opportunity and a risk
When semiconductors make up half of exports, the semiconductor cycle becomes the cycle of Korean exports and KOSPI. When prices rise, as in 2026, the overall numbers look dazzling, but when memory prices turn down, as in 2023 in Lesson 3, exports and the stock market can shake together. So the larger the , the more you need the habit of tracking 'non-semiconductor exports' and the semiconductor price trend separately.
Generally favorable when exports are strong
Semiconductors · Autos · Shipbuilding · Machinery
For sectors with a high export share, rising exports directly means rising revenue and profit. When cargo volume grows, it also helps transport sectors such as shipping and air cargo.
Little direct effect from exports
Banks · Insurance · Domestic consumption
Sectors whose core business is domestic lending and consumption are little affected directly by export numbers. They do benefit indirectly, though, when strong exports improve the economy and incomes.
For stocks, like this: the order for reading the 1st of each month
| Order | Number to look at | Question |
|---|---|---|
| 1 | Total and growth rate | Was it better or worse than the market forecast? (Lesson 20) |
| 2 | Daily average exports | Does it point the same way once the working-day difference is removed? |
| 3 | Exports by item | Semiconductors vs. non-semiconductors; was it thanks to price or volume? |
| 4 | Exports by region | Where did exports grow or shrink: China, the US or ASEAN? |
| 5 | Trade balance and imports | What is the reason for the surplus? What effect does it have on dollar inflows and the exchange rate? (Lesson 24) |
You can check the next release date in the Calendar, and how the current export phase is reflected in the environment scores by sector under the 'Export growth' factor on the Macro Map. It also helps to look at recent sector trends together with the Theme Map.
Not always. The correlation between exports and KOSPI is only a historical average, and in years when interest rates and investor sentiment move the multiple knob a lot, the two walk separately. Also, many sectors in KOSPI have little to do with exports.
Quick checkA record-high export figure was announced, yet KOSPI fell that day. What reasons can you think of?
✓What we learned today
- The Ministry of Trade and Industry releases the previous month's trade statistics on the 1st of each month. You need to look together at the total and the year-over-year growth rate, the daily average exports adjusted for working days, exports by item and region, and the trade balance.
- Export value is price × volume. The +262.8% in semiconductor exports in September 2026 owed a lot to the surge in memory contract prices, and the semiconductor share of exports grew from about 21% in 2024 to about 50% in September 2026.
- Exports move the earnings knob of Korean companies. In monthly data from 2015 to 2026, the correlation coefficient between export growth and KOSPI's one-year return was 0.72.
- KOSPI has tended to move several months before exports. When KOSPI was placed 3–4 months ahead of exports, the correlation coefficient rose to 0.83–0.85. The market prices in exports 'in advance'.
- High growth rates mix in the base effect and working days, and concentration in one item means the whole market risks being shaken by that item's cycle. A trade surplus is not a good signal either if it came from shrinking imports.
When the export report card improves, overseas investors also buy more Korean stocks, and the exchange rate moves in the process. The next lesson looks at how foreign investors calculate both stock-price returns and currency returns together, and how foreign net buying and the USD/KRW rate have interlocked.
Quiz5-question quiz
Pick an answer and it's graded right away with an explanation.
Q1. In the monthly trade statistics the Ministry of Trade and Industry releases on the 1st, which number should you look at to remove the effect of a different number of working days caused by holidays?
Daily average exports is total exports divided by the number of working days. In September 2026 there were fewer working days because of the Chuseok holiday, so the total was +83.5% and the daily average was +105%.
Q2. Export value doubled in a year, but export volume was unchanged. What lifted exports?
Export value = price × volume. If volume is unchanged, price doubled. The surge in the DRAM contract price also played a big part in the September 2026 jump in semiconductor exports.
Q3. In the 2015–2026 data, when KOSPI was placed 3–4 months ahead of exports, the correlation coefficient rose from 0.72 to 0.83–0.85. What does this mean?
That KOSPI's past values matched better when paired with exports a few months later means that stock prices priced in exports in advance and moved first.
Q4. In the first half of 2022, exports grew but KOSPI fell sharply. How would you explain it with the two knobs of Lesson 1?
Exports supported the earnings knob, but the rapid rate hikes in Korea and the US sharply reduced the multiple the market was paying.
Q5. What is the most important thing to watch out for when looking at a trade surplus?
A 'recession-type surplus' created by shrinking imports can be a sign of a slowing economy even though it is a surplus. You need to look at the reason for the surplus as well.
NextTerms · Next lesson · Related tools
Selling goods and services made at home to other countries. Money from abroad comes in as sales for domestic companies. Korea is a country with a large export share, about 41% of GDP (2023).
Net exportsNet exportsExports minus imports. What overseas buyers take of our output is added to GDP, and what we buy from abroad is subtracted.
Monthly trade statisticsMonthly trade statisticsThe previous month's export, import and trade balance results, which the Ministry of Trade and Industry releases on the 1st of every month from Korea Customs Service clearance data. It is the fastest big economic indicator, coming out as soon as the month turns, so the market pays attention.
Daily average exportsDaily average exportsTotal monthly exports divided by the number of working days (days worked). It removes the illusion caused by different numbers of working days due to holidays and the like, showing the real momentum of exports.
Trade balanceTrade balanceGoods exports minus imports. A surplus brings more dollars into the market and pushes toward a stronger won, while a deficit pushes toward a weaker won. It is released by the Ministry of Trade, Industry and Energy on the 1st of each month.
Export price and volumeExport price and volumeExport value is price × volume. Exports that grew thanks to price raise margins a lot but can reverse quickly when the price cycle turns.
Export concentrationExport concentrationThe degree to which exports are concentrated in one or two items. The semiconductor share was about 21% in 2024 and 24.4% in 2025, and grew to about 50% by September 2026. The greater the concentration, the more that item's cycle shakes exports and the whole stock market.
Base effectBase effectA phenomenon in which the number at the comparison base date is unusually high or low, so the current rate of change looks lower or higher than the actual trend. It often appears when reading year-over-year indicators.
YoYCompared with the same month a year earlier, YoY (Year over Year)The rate of change compared with the same month (or quarter) a year earlier. It removes seasonal effects and shows the change accumulated over a year, so it is the basic number for inflation releases.
Price cyclePrice cycleA pattern in which supply reacts slowly to changes in demand, so prices rise too far and then fall too far, repeatedly. It is especially pronounced in memory semiconductors, chemicals and shipping.
EarningsEarningsThe money a company has left after subtracting cost of sales, expenses, interest and taxes from revenue (net income). It is the most basic factor that determines the stock price.
Priced inPriced inA state in which something expected to happen is already reflected in prices such as stock prices or interest rates. If things happen as expected, prices do not move much.
This is educational material and not investment solicitation. There is no guarantee that past relationships will repeat in the future.