Following the capital gains tax (yangdo-se jungkwa) surcharge that took effect on May 10, Seoul apartment transactions in June fell sharply compared to the previous month. According to Yonhap News, the common market diagnosis is that wait-and-see sentiment spread ahead of tax reform, causing transactions themselves to decline. When transaction volume drops, sale prices lose direction while jeonse prices, reflecting real demand, tend to be relatively stable or converge faster. The ratio of these two numbers—jeonse-gayul (jeonse-to-price ratio)—is the most direct indicator for gauging gap risk in an uncertain market like this one.

Aerial view of Seoul apartment complexes

What Is Jeonse-gayul and Why Does It Matter Now?

Jeonse-gayul is straightforward: it is the ratio of the jeonse deposit to the sale price. If a KRW 1 billion apartment carries a KRW 700 million jeonse deposit, the jeonse-gayul is 70%. This single number determines the size of the gap. A 70% jeonse-gayul means a KRW 300 million gap; at 60%, the gap is KRW 400 million. The smaller the gap, the less capital is needed to buy, but at the same time even a small dip in jeonse prices can leave the landlord unable to return the deposit.

In an active market, sale prices and jeonse prices move together, making sharp swings in jeonse-gayul unlikely. However, as Yonhap News reported, when an external variable like the capital gains surcharge sharply reduces transaction volume, sale transactions stop while jeonse contracts continue. This out-of-sync movement can pull jeonse-gayul in unexpected directions. If jeonse prices fall while sale prices are stuck near a peak, jeonse-gayul declines and the gap widens. Conversely, if sale prices correct first, jeonse-gayul rises and the gap shrinks—but now the buyer's loss potential becomes the focal point.

Adding to this, prosecutors have launched a crackdown on real estate speculation and price manipulation. According to Yonhap News, dedicated prosecutors have been assigned nationwide in line with the Lee Jae-myung administration's price stabilization stance. This is not a direct regulation of gap investment (gap-tuja), but it is clear that the legal risk of artificially inflating prices has increased. In this context, the ability to read jeonse-gayul "as numbers" becomes even more important for end-buyers.

How to Verify Jeonse-gayul Directly

There are three main ways to check jeonse-gayul: the Ministry of Land, Infrastructure and Transport's Real Transaction Price Disclosure System; weekly statistics from the Korea Real Estate Board; and private data services (such as Hogangnono or Asil). The reason the numbers differ across these three sources is differences in reference date and sampling methodology. The real transaction price system is closest to "fact" because it is based on reported contracts, but there is a time lag in updates; weekly statistics use a sample survey and may not accurately reflect individual complexes.

Therefore, to assess the gap risk for a specific complex, a three-step approach is reasonable. First, find the average sale transaction price for the same unit size at that complex over the past six months. Second, find the average jeonse transaction price for the same period. Third, divide the two numbers to calculate jeonse-gayul directly. The condition "same period" matters here. If the sale and jeonse transaction dates diverge significantly, market conditions will have changed enough to distort the ratio.

Jeonse-gayul shows you the size of the gap while simultaneously asking how long that gap can hold.

To get a fuller three-dimensional view of gap risk, you should also look at the trend of jeonse-gayul. Even if jeonse-gayul is 70% today, if it was 80% a year ago, the gap is widening. If it was 60% a year ago, the trend is actually converging. The direction is just as important as the current figure—sometimes more so. In a market where transaction volume has dropped, this direction can reverse sharply, so judging by short-term data alone is risky.

Real estate contract documents and a calculator

A Small Gap Does Not Mean Safety — Hidden Variables

A high jeonse-gayul and a small gap lower the barrier to entry for buying. But a "small gap" does not automatically mean "low risk." Several hidden variables lurk behind the jeonse-gayul number.

The first is the substantiveness of jeonse demand. Whether a jeonse contract reflects genuine residential demand or temporary demand makes a difference in the durability of the jeonse price. Complexes slated for reconstruction or redevelopment sometimes see jeonse prices temporarily rise on relocation demand, pushing jeonse-gayul up—but as the project progresses, jeonse demand disappears and jeonse prices can collapse sharply.

The second is non-monetary variables such as noise or defects. A court recently ruled that a sale contract for an apartment was justifiably cancelled because the seller failed to disclose severe noise from an underground mechanical room. According to Yonhap News, the court found that knowingly concealing the noise constituted grounds for contract rescission. Complexes with such defects may have a high jeonse-gayul, but once the defect becomes public, jeonse prices can plummet and the gap can widen overnight. This is why verifying the physical reality behind the numbers matters.

The third is the supply variable. The government has announced a plan to supply 310,000 housing units by 2031, and redevelopment projects near Yongsan Station are also accelerating. In areas where new supply is concentrated—or in their immediate vicinity—jeonse prices may be suppressed by increased jeonse supply, causing jeonse-gayul to fall. There is no guarantee that today's jeonse-gayul will hold up against future supply plans.

Verification Item Low-Risk Signal High-Risk Signal
Jeonse-gayul level 50–65% stable range Above 80% (gap very small)
Jeonse-gayul direction Flat or rising over past year Continuously declining over past year
Transaction volume trend Both sale and jeonse transactions normal Sale transactions sharply down, only jeonse transacting
Nearby supply plan None or small-scale Large presale or relocation scheduled
Complex defects or special circumstances None noted History of noise, defects, or disputes

Things to Verify

  • Have you checked the past six months of sale and jeonse transaction prices for the complex and unit size of interest in the Ministry of Land's real transaction price disclosure system?
  • After calculating jeonse-gayul directly, did you compare it with the same period a year ago to understand the direction?
  • Have you checked HUG (Korea Housing Finance Corporation) or the Korea Real Estate Board's presale schedule for the volume of units scheduled to move in within 1–2 km of the complex between 2026 and 2031?
  • Have you checked the registry certificate and building ledger for any history of noise, defects, or legal disputes at the complex?
  • If the property you wish to buy has a sitting jeonse tenant, have you confirmed the jeonse expiry date and whether the tenant has exercised their right to request contract renewal?
  • Have you checked how the number of actual transactions in the area changed after the capital gains surcharge took effect, and how long the wait-and-see sentiment has persisted, using weekly transaction volume data?

References