The Building That Is 99.7% Full
Somewhere in Gangnam, there is an office tower with roughly three empty desks for every thousand. That is not a figure of speech. In the second quarter of 2026, the vacancy rate across Gangnam’s ultra-large buildings sat at 0.3%, according to the Korean brokerage RSQUARE. Large buildings in the same district managed 2.2%. Meanwhile, across the river, brand-new towers in the old downtown were opening with entire floors dark.
Welcome to the Seoul office market, where the usual laws of supply and demand appear to have been suspended. Vacancy rose last quarter. Seoul office rents rose too. Both records landed in the same city, in the same three months. For anyone used to reading Manhattan or London vacancy charts, the combination looks like a typo.
It is not. Instead, it is the clearest picture yet of a Seoul office market splitting into two separate economies. Understanding why matters if your company is scouting a Korean headquarters, if you are weighing Korean REITs, or if you simply want to know where Korea’s money is moving in 2026.
Seoul Office Market Basics: Three Districts, Three Economies
Before the numbers make sense, the geography has to.
Seoul does not have one downtown. Rather, it has three, and Korean research reports refer to them by abbreviations that nobody bothers to explain to foreigners.
CBD is the Central Business District. It covers Gwanghwamun, Jongno, and Euljiro, wrapped around the old palaces. Traditionally, banks, conglomerate headquarters, law firms, and government-adjacent institutions cluster here. It also holds the city’s oldest office stock, and consequently the most buildings due for replacement.
GBD is the Gangnam Business District, south of the Han River. Originally farmland, it was developed from the 1970s onward. Today it is Korea’s technology heartland. Naver affiliates, gaming studios, venture funds, and increasingly AI companies all sit here. Notably, land constraints mean Gangnam almost never receives large new supply.
YBD is Yeouido, an island in the Han River that functions as Korea’s Wall Street. Securities houses, asset managers, insurers, and the National Assembly share a patch of land you can cross on foot in twenty minutes.
Each district behaves like a separate country. As a result, a single citywide number tells you very little about the Seoul office market. The second quarter of 2026 delivered that lesson with unusual force.
Vacancy Up, Seoul Office Rents Up: The Quarter That Broke the Pattern
Here are the headline figures for Q2 2026, as reported by RSQUARE.
Average office vacancy across Seoul climbed to 6.5%, up 0.4 percentage points quarter-on-quarter. Furthermore, this was the first increase in four quarters. A long tightening streak had finally ended.
Ordinarily, rising vacancy means falling rents. Landlords compete. Incentives appear. Effective rents drift down. However, none of that happened this time. Large-office rents in the CBD rose 8.5% year-on-year, the strongest gain of the three districts. Headline rents across prime stock hit fresh records.
Other research houses found the same contradiction using different arithmetic. JLL recorded net effective rents of ₩152,800 per pyeong per month. That was up 2.2% on the quarter and 4.9% on the year. Cushman & Wakefield, meanwhile, put average rent growth at 5.0% year-on-year.
Savills logged something genuinely historic. Gangnam’s average prime nominal rent reached ₩136,200 per pyeong, edging past the CBD’s ₩135,200. Since Savills began tracking the Seoul office market in 1997, Gangnam had never been the most expensive district in the city. In 2026, it finally was.
A quick translation for readers outside Korea. A pyeong is 3.3 square metres, or about 35.5 square feet. So ₩131,300 per pyeong per month works out to roughly US$29 per square metre per month. Annually, that is about $32 per square foot. Compared with Midtown Manhattan, Seoul office rents look cheap. Compared with most of Asia outside Tokyo, Hong Kong, and Singapore, they look expensive.
The Supply Wave That Hit the Seoul Office Market
So why did vacancy rise at all? Because eleven new buildings opened at once.
Roughly 99,000 pyeong of new space was delivered in a single quarter. In metric terms, that is about 327,000 square metres, or 3.5 million square feet. More than 60% of it landed in one district. Specifically, the CBD absorbed 61,642 pyeong, concentrated in two towers: G1 Seoul at 43,388 pyeong and Rene Square at 12,587 pyeong, both near Euljiro.
Consequently, CBD vacancy jumped to 7.3%, a rise of 2.4 percentage points in three months. By JLL’s stricter Grade A definition, the same district hit 12.3%. Cushman & Wakefield put it at 9.0%. Whichever figure you prefer, the direction is identical. The cause is identical too: two big buildings opened empty, exactly as new buildings always do.
Gangnam, by contrast, received no new supply whatsoever. Hence the 0.3% figure. Nothing was added. Nothing was vacated in volume. Demand simply had nowhere else to go.
This distinction matters more than it sounds. When vacancy rises because tenants leave, a market is weakening. Yet when vacancy rises because inventory arrives, a market is expanding. CBRE Korea made exactly this point. Stripping out newly completed assets, vacancy in existing buildings actually fell during the quarter.
Flight to Quality, Without the Jargon
Property analysts have a phrase for what is happening here: flight to quality. In plain terms, Korean companies are abandoning old buildings for new ones. Moreover, they are willing to pay a premium for the move.
Several forces push in the same direction at once.
First, there is the return-to-office calculation. Korean firms never embraced remote work the way American ones did. So the question was never whether staff would come in. Rather, it was whether the office was good enough to make them want to. A 1990s building with low ceilings and creaking HVAC loses talent to a glass tower with a decent cafeteria.
Second, ESG reporting has quietly become a leasing criterion. Large Korean corporates now disclose building-level energy performance, and their foreign partners increasingly ask for it. Older stock fails those tests. Retrofitting, meanwhile, is expensive.
Third, and most practically, refurbishment costs have exploded. Construction inflation has run hot in Korea since 2022. That pressure is a big part of why the Korea PF crisis 2026 hit developers so hard. For the owner of a 1998 building, the maths of a full modernisation frequently no longer works. Therefore, the building slides down-market instead, and its tenants go shopping.
The result is a widening gap inside the Seoul office market. Prime assets set records. Meanwhile, secondary stock quietly accumulates the vacancy that the headline number is actually measuring.
Gangnam Office Vacancy and the Arrival of the AI Tenant
The most interesting story in the Seoul office market right now is who is filling Gangnam.
For two decades, Gangnam meant startups, gaming, cosmetic clinics, and cram schools. Increasingly, though, it means artificial intelligence. Cushman & Wakefield’s 2026 Seoul office tenant report identified the district as Korea’s emerging AI hub. The anchor example is hard to miss: Anthropic, the American lab behind Claude, established its Korean base at Centerfield in Gangnam.
That single lease says a great deal. Global AI firms entering Korea are not picking the financial district or the government district. Instead, they are picking the district where Korean engineers already work, where venture capital already sits, and where Korea’s AI data center buildout keeps its commercial front office.
Traffic runs the other way too, which complicates the picture. MetLife Korea and Lotte Rental both relocated out of Gangnam and into the new CBD towers. Gangnam still posted the lowest Gangnam office vacancy in the city. Its tenant mix, however, is churning faster than the headline suggests.
Elsewhere, Yeouido is doubling down on what it already is. Woori Investment Securities and the Korea Trade Insurance Corporation both expanded there. The island is reinforcing its financial cluster rather than diversifying it.
For companies deciding where to land, the pattern is now fairly legible. Finance goes to Yeouido. Tech goes to Gangnam. Legacy corporate and government-facing work stays in the CBD. Meanwhile, cost-sensitive engineering teams keep drifting south to Pangyo, whose trade-offs we have covered separately.
Korea Commercial Real Estate Deals: A ₩811 Billion Record
Leasing tells one story about the Seoul office market. Investment tells another, louder one.
Office transaction volume across Seoul and neighbouring Bundang reached roughly ₩6 trillion in Q2 2026, or about US$4.4 billion. That figure is about 1.7 times the ₩3.5 trillion recorded in the first quarter. JLL, counting a narrower universe of institutional-grade deals, logged ₩4.0 trillion instead.
The headline transaction came in June. Hana Securities exercised a right of first refusal and bought its own Yeouido headquarters from Koramco The One REIT. The price was approximately ₩811.2 billion, or around US$590 million. At roughly ₩38.4 million per pyeong, it set a record for Yeouido. By JLL’s count, it was also the largest single office trade in nearly five years. That one building accounted for 28.9% of all Seoul commercial property transaction value that month.
RSQUARE additionally logged the IFC office component at about ₩1.93 trillion, making it the quarter’s largest recorded deal. IFC has been Korea’s longest-running property soap opera. Brookfield has been trying to exit since 2021. A ₩4.1 trillion sale to Mirae Asset collapsed in 2022, and Singapore-linked ARA has been circling since 2024. Anyone valuing Korean landmark assets should therefore treat headline IFC numbers with appropriate caution.
One statistic cuts against the celebratory mood. The average price per pyeong across all Q2 deals fell 11.1%, to ₩27.19 million. In other words, volume was not driven by everything getting more expensive. Rather, it was driven by more assets trading, including plenty of secondary buildings changing hands at unexciting prices. Trophies set records. The middle of the market did not.
Nobody Agrees on the Seoul Office Market Vacancy Rate
If you research this topic yourself, you will encounter four different vacancy figures for the same three months. Here they are, side by side.
| Research house | Seoul vacancy, Q2 2026 | CBD | GBD | YBD |
|---|---|---|---|---|
| RSQUARE | 6.5% | 7.3% | 0.3% (ultra-large) / 2.2% (large) | — |
| JLL (Grade A) | 6.6% | 12.3% | 0.9% | 4.8% |
| Cushman & Wakefield (Class A) | 5.8% | 9.0% | 3.1% | 3.7% |
| CBRE (prime) | 4.2% | 6.6% | 1.3% | 3.1% |
None of these firms is wrong. Instead, each defines its sample differently. Some count only Grade A towers above a floor-area threshold. Others include mid-size buildings. Some measure physical vacancy, while others measure availability, which includes space marketed but not yet empty. CBRE’s prime-only universe is naturally tighter than RSQUARE’s broader one.
For readers, the practical lesson is simple. Compare like with like. Track one source over time rather than mixing them. Above all, treat any single vacancy headline for the Seoul office market as an opinion with a methodology attached. You can check the underlying reports yourself at Cushman & Wakefield Korea and JLL, both of which publish quarterly in English.
Who Is Actually Buying Korea Commercial Real Estate
Ownership in the Seoul office market has a distinctive structure, and foreigners frequently misread it.
Domestic institutions dominate. Pension funds, insurers, securities firms, and their affiliated asset managers own most of the prime stock. Typically, they hold it through private real estate funds rather than listed vehicles. Occupier-owners are common too. The Hana Securities deal is a textbook case: a Korean financial firm buying the building it already occupies, partly for balance-sheet reasons and partly for prestige.
Foreign capital participates, though selectively and cyclically. Brookfield’s IFC saga is the cautionary tale everyone cites. Nevertheless, sovereign and pan-Asian funds remain active in logistics and data centres.
Listed REITs offer the most accessible route for individual foreign investors. Korea’s listed REIT market is young and small by regional standards. The Korea Association of REITs currently lists 24 vehicles, weighted heavily toward a handful of large sponsors such as SK REIT and KB Star REIT. Dividend yields have historically looked attractive next to Korean government bonds. On the other hand, liquidity is thin, and share prices stay sensitive to rate expectations. The Bank of Korea’s base rate sat at 2.75% through the second quarter, and financing costs remain the single biggest swing factor for returns.
Direct purchase is a different matter entirely. Korea has tightened its foreign acquisition regime considerably, and the current permit requirements appear in our guide to Korea’s foreign property rules. Holding costs deserve equal attention, since Korea’s 2026 property tax rewrite reshaped the arithmetic for commercial owners as well as residential ones.
Leasing an Office in Seoul: What Surprises Foreigners
For companies rather than investors, the Seoul office market differs from Western norms in several specific ways.
The deposit is enormous. Korean commercial leases typically require a security deposit of roughly ten months’ rent. It is paid upfront and refunded at the end. For a large lease, that is a serious working-capital commitment. Furthermore, it is rarely negotiable below a certain floor.
Rent is only part of the cost. A separate management fee, or gwanribi, covers building services. Commonly, it adds 30% to 40% on top of headline rent. Consequently, quoted Seoul office rents understate your real occupancy cost. Ask instead for the net occupancy cost, which Korean brokers abbreviate as NOC.
Rent-free periods exist, but they move with the cycle. In tight submarkets like Gangnam, incentives have all but vanished. In the CBD’s newest towers, however, landlords currently have empty floors to fill. So concessions are back on the table there. This is precisely where the vacancy split becomes a negotiating lever.
Fit-out is on you, and it is not cheap. Korean offices usually arrive as bare shell. Cushman & Wakefield publishes an annual South Korea fit-out cost guide, which is worth reading before you set a budget.
Leases are shorter than you expect. Two to three years is standard. Five-year terms are generally reserved for anchor tenants. Therefore, the leverage cycle turns over quickly for both sides.
For smaller teams or a first landing, flexible space remains the sensible entry point. Seoul has an unusually deep bench of it, as our complete list of coworking spaces in Seoul shows.
The 2028 Problem Facing the Seoul Office Market
Finally, there is the thing every Korean analyst is privately watching.
The CBD has roughly 36 development projects totalling about 770,000 pyeong in the pipeline through 2029. To put that in context, average annual supply has historically run around 52,000 pyeong. The planned pace is closer to 134,000 pyeong a year. For 2027 through 2029 specifically, it rises to roughly 190,000 pyeong annually, or nearly four times the historic norm.
If everything gets built on schedule, CBD vacancy could approach 12% by 2028. Natural vacancy, for comparison, sits near 5%. That scenario assumes no slippage, however. Given financing conditions and the number of projects still awaiting groundbreaking, a more realistic path puts CBD vacancy near 9% in 2028 and around 15% in 2029, as delayed projects bunch up later in the decade.
Either way, the direction is clear. The CBD is heading into a tenant’s market. Gangnam, with no meaningful pipeline and an AI cluster still forming, is heading the other way.
That divergence is the real story of 2026. The Seoul office market is not one market with a 6.5% vacancy rate. Instead, it is two markets wearing the same statistic. Downtown is absorbing the biggest construction wave in its history. South of the river, the newest and best buildings are effectively full, and the rent crown has changed hands for the first time since 1997.
For anyone choosing where to put a Korean headquarters, or a Korean allocation, those are not the same bet at all.
