Invest1 publisher3 min readPublished
Korea's 19-month climb up the OECD leading index has slowed to 0.06 point a month
Korea's composite leading indicator reached 102.87 in August, the highest of the 17 countries the OECD publishes. The monthly gains that got it there have narrowed in each of the last five months.
The Investor · Invest desk
What happened
- August's reading was a 19th consecutive monthly rise for Korea's OECD composite leading indicator and put the country in first place for the first time since May 2020.
- Korea ranked 16th of 17 countries last September, reached third in February, took second from Mexico in July, and in August passed Brazil, which had led for eight months.
- The month-on-month gain peaked at 0.43 point in March and has narrowed every month since, printing 0.41, 0.37, 0.28, 0.15 and then 0.06 in August.
- August exports rose 68.7% from a year earlier, lifted by expanded shipments of semiconductors, computers and cosmetics.
- Korea's three-year treasury yield rose above 4% on the 11th for the first time since November 2023, and the 10-year reached its highest since October 2022.
Compiled by The InvestorSomething wrong?How this is made
Why it matters
- contradiction The Finance Ministry rests its case on the height of the index and the slowdown case rests on the slope of the same monthly series, so the next print decides the question rather than the argument.
- exposure Households and companies pay for the two consecutive base rate rises now, before anyone can confirm whether the cycle is still accelerating.
- constraint Korea's forecast advantage rests on a price ratio it only half controls, because crude sets the import side of it.
- precedent A negative September gain would leave the OECD's own indicator calling a peak while the government's Green Book still describes a solid recovery.
The narrowing is regular enough to extend. Korea's monthly gain shed 0.37 point between March's 0.43 and August's 0.06 [11], about 0.074 a month, and one more month at that pace puts the September change at minus 0.01 [1]. August's gain is roughly a seventh of March's [6].
The level is 0.01 point off the record, 102.87 against 102.88 in May 2021 [2]. A September gain of 0.02, a third of August's, would take the index past that high while the monthly series keeps deteriorating [2].
The run behind it: the index bottomed at 99.14 in January 2025, crossed the 100 line in November 2025 at 100.12, and has risen in every month since February 2025 [4][1]. That is 3.73 points in 19 months, an average of 0.196 a month, so August's 0.06 is about 31% of the run's own average [4]. April through August added 1.27 points between them, which puts the March reading near 101.60 [3].
The domestic gauge shows the same shape. The National Data Agency's cyclical leading component rose for nine straight months to 104.2 in July, its highest since August 2000 [7], and its monthly gain fell to 0.4 point from 0.9 in June [12].
The OECD builds the CLI to describe GDP six to nine months out, with a reading above 100 pointing to growth above the long-run trend [3]. August's print therefore covers roughly February to May 2027 [5], and at 2.87 points above the baseline [7] it forecasts above-trend growth in that window even if it has topped out.
Improved terms of trade from the semiconductor boom is cited as the main driver of the index, and terms of trade is export prices divided by import prices [9]. Oil above $100 a barrel raises the denominator [13]. Korea's exports rose 68.7% from a year earlier in August [10], though that is value growth, not a price index, so the ratio cannot be read off it.
Two of the six components are financial, share prices and the spread between short and long rates [8]. The yield move on the 11th runs through the index and through company balance sheets at once, and the Bank of Korea has raised its base rate twice in a row, which the report links to heavier funding costs for companies and interest burdens for households [16].
The Ministry of Finance and Economy's September Green Book said the economy "appears to be maintaining a solid recovery" [17]. A ministry official said: "Whether measured by the OECD or by the National Data Agency, the leading index is at a very high level, overwhelmingly ahead of major countries" [18]. The same official said that "with the index well above 100, a slower month-on-month gain should not be read as the economy turning down" [19].
Both arguments come out of one series. The level is a forecast the OECD has already issued for next spring, and the slope indicates what the next one will say; I'd expect September flat or negative. I would be wrong if the gain jumps back above July's 0.15 [11], or if semiconductor export prices keep rising faster than the import bill, in which case terms of trade goes on contributing [9]. There is also the comparative point, since Korea sat 16th of 17 last September and took first place by passing Brazil, which had led for eight months [6].
What to watch
- The September CLI print: whether the monthly gain stays positive and whether the index clears 102.88.
- The National Data Agency's August cyclical component, after its monthly gain halved to 0.4 point in July.
- Whether semiconductor export prices keep rising faster than the oil import bill while crude holds above $100.