Korea's 2.9% inflation print conceals a 0.4-point pickup once the telecom base effect is removed
South Korean consumer prices rose 2.9% in September, a pace 0.4 points faster than August once last year's telecom-discount base effect is removed. Core inflation is at about its highest this year, and the Bank of Korea sees October near 3%, against a 2% target.
The Investor · Invest desk
What happened
- Discounts SK Telecom gave after last year's hacking incident depressed prices last August, so this August's 3.1% would have been about 2.5% without that base.
- August's core reading of 3.4% falls to around 2.8% once the telecom effect is removed, the same rate core printed in September.
- The government said its price ceiling on oil products lowered September inflation by 0.6 points and that the rate would have been 3.5% without it.
- Agricultural prices fell 4.0%, cutting 0.17 points from the headline, as apples and pears dropped 10.9% on a strong harvest and pre-Chuseok shipments.
- The September figure matched the median forecast in a Reuters poll of economists.
Why it matters
- What it limits constraint Lifting the oil price ceiling would push the published rate toward 3.5%, 1.5 points over the 2% target, so the government is tied to the cap while crude stays high.
- What doesn't add up contradiction The Bank of Korea's deputy governor expects October near 3% while a finance ministry official sees the high 2% range, so the two agencies disagree on which side of 3% the next prints land.
- Who's exposed exposure With like-for-like core stuck at 2.8%, any further fall in headline inflation depends on crude and post-holiday farm prices, the two parts the government is managing directly.
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If you accept the adjusted August figure, about 0.6 points of the published 3.1% came from last year's telecom discount [18]. September has no such distortion. Seoul Economic Daily puts the like-for-like acceleration at 0.4 points [14]. The monthly series points the same way, with prices up 0.3% in September after 0.2% in August [17]. The Bank of Korea held a price review meeting the same day and said the pace of increases had somewhat widened now that the temporary base effect was gone [15].
The August core reading was inflated by the same amount, about 0.6 points [22]. Adjusted, core did not move between the two months [23]. Seoul Economic Daily still calls 2.8% effectively the year's highest core reading. Processed food rose 2.1%, computers 27.4% on semiconductor component costs, and mobile phones 8.3% after shipment price rises on new models [8][9]. With the adjusted headline up 0.4 points and adjusted core flat, the pickup came from the food and energy items that core leaves out [24].
Those items moved in opposite directions. "Agricultural, livestock, and fisheries prices fell year-on-year for a second consecutive month, supported by targeted government measures ahead of the Chuseok holiday," the finance ministry said in a statement [12]. Inside that group, livestock rose 3.7% and fishery products 4.5% on reduced supply and holiday demand [6]. Fuel is where the two reports differ. Seoul Economic Daily has oil products up 14.8% on higher crude [7]. CNA has petroleum products up 11.8% and diesel up 20.0% [13].
Both fuel figures are measured under the ceiling. Add back the cap's 0.6 points and the 0.17 points that farm prices subtracted, and an unmanaged September comes to roughly 3.7% (assuming the two effects simply add) [25]. Even the managed 2.9% is 0.9 points above the 2% target [19].
The case for sticky inflation could weaken in two ways. Crude could fall far enough that lifting the ceiling adds little to the index. Or the farm price decline, which the ministry credits partly to its own holiday measures, could last beyond Chuseok. The counter-thesis on core is simpler. A core rate of 2.8% two months running is flat, and a central bank could treat a flat core as room to look past a fuel spike it did not cause.
I think the data argue against a Bank of Korea cut soon. The adjusted headline is rising, core is at the year's high, and the government is keeping 0.6 points out of the index through the oil price ceiling [2]. The reports do not cover the policy rate or the bank's guidance on it. An October print in the high 2% range with core below 2.8% would undercut this view.
What to watch
- October's CPI release, and whether core drops below the 2.8% it has held on a like-for-like basis for two months.
- Whether the government extends or lifts the oil price ceiling it credits with taking 0.6 points off September inflation.
Information, not investment advice. This story is general information about companies and markets, drawn from cited reporting. It is not a recommendation to buy, sell or hold any security; check the cited sources before acting.
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- Evidence78
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- [1]
South Korea's consumer price index stood at 120.43 in September (2020 = 100), up 2.9% from a year earlier, according to Statistics Korea's report released on October 2.
- [2]
The government said its price ceiling program for oil products lowered September inflation by 0.6 percentage points and that without the ceiling price growth would have reached 3.5%.
- [3]
Consumer price growth was 3.1% in May, 3.2% in June, 2.8% in July and 3.1% in August; September's rate remains above the Bank of Korea's 2% inflation target.
- [4]
Telecom bill discounts following last year's hacking incident at SK Telecom temporarily depressed prices in August of last year; excluding that base effect, price growth in August of this year was about 2.5%.
- [5]
Agricultural, livestock and fishery prices fell 0.3%, a second monthly decline; agricultural prices alone fell 4.0%, trimming 0.17 percentage points from overall inflation, and apples and pears fell 10.9% on a strong harvest, increased pre-Chuseok shipments and government discount support.
- [6]
Livestock prices rose 3.7% and fishery product prices 4.5%, driven by reduced supply and stronger Chuseok demand.
- [7]
Prices of oil products rose 14.8% on higher international crude prices.
- [8]
Core inflation, excluding food and energy, rose 2.8% in September, effectively the highest level this year, as price gains in processed food and durable goods widened.
- [9]
Processed food prices rose 2.1%; computer prices rose 27.4% on higher semiconductor component costs; mobile phone prices rose 8.3% after manufacturers raised shipment prices for new models.
- [10]
Lee Ji-ho, deputy governor at the Bank of Korea, said consumer price growth in October is expected to stay near 3% as price gains in core items continue.
- [11]
An official at the Ministry of Economy and Finance said upside risks remain, including higher international oil prices and grain price swings, and that there is a strong chance consumer price growth will run in the high 2% range from October onward.
- [12]
"Agricultural, livestock, and fisheries prices fell year-on-year for a second consecutive month, supported by targeted government measures ahead of the Chuseok holiday," the finance ministry said in a statement.
- [13]
Industrial product prices rose 4.2% from a year earlier, driven largely by petroleum products, which rose 11.8%; diesel prices rose 20.0%.
- [14]
On the basis excluding the telecom base effect, September inflation was 0.4 percentage points higher than August.
- [15]
The Bank of Korea held a price review meeting the same day and said that, given the disappearance of August's temporary base effect, the pace of price increases had somewhat widened.
- [16]
September's 2.9% CPI rise matched the 2.9% median forecast in a Reuters poll of economists.
- [17]
On a monthly basis consumer prices rose 0.3% in September after a 0.2% gain in August.
- [18]
About 0.6 percentage points of August's published 3.1% inflation came from the telecom discount base effect.
- [19]
Published September inflation of 2.9% is 0.9 percentage points above the Bank of Korea's 2% target.
- [20]
Without the oil price ceiling, September inflation of 3.5% would be 1.5 percentage points above the 2% target.
- [21]
Core inflation was 3.4% in August, but excluding the telecom discount base effect it was around 2.8%.
- [22]
The telecom base effect added about 0.6 percentage points to August core inflation.
- [23]
On a like-for-like basis, core inflation was unchanged between August and September at about 2.8%.
- [24]
With adjusted headline inflation up 0.4 points and adjusted core unchanged, the September pickup came from the food and energy components that core excludes.
- [25]
Adding back the oil price cap effect and the drag from falling agricultural prices gives an unmanaged September rate of roughly 3.7%, assuming the effects are additive.
Sources
3 independent publishers whose own reporting we read for this story.
- channelnewsasia.comSouth Korea September inflation eases to 2.9% year-on-year, matches forecast
2 articles · October 1, 2026
- en.sedaily.comKorea's September Inflation Slows to 2.9% After Two Months Above 3%
3 articles · October 2, 2026
- en.yna.co.krConsumer prices up 2.9 pct in Sept., fall to 2 pct levels
4 articles · October 1, 2026
- koreajoongangdaily.comConsumer prices up 2.9% in September
1 article · October 1, 2026
Topics and entities
Topics
- Consumer price inflation
- South Korean monetary policy
- Base effects in inflation data
- Fuel price controls
Entities
- Bank of Korea
- Ministry of Economy and Finance
- SK Telecom
- Statistics Korea