Case Studies
Case Study: 중산층 1-주택자 Couple and the 종합부동산세 혜택 – How to Maximize Savings
A down-to-earth scenario showing how a married couple owning one home can benefit under the latest property tax exemption and special rules (종부세 합산배제 & 과세특례).
By NomadicTax Research Team • 5-8 min read • September 16, 2026
## Scenario Overview
Meet **Mr. and Mrs. Kim**, a married couple co-owning a single residential property in Seoul. They live there permanently and no other family member owns real estate. Their home’s 공시가격 (officially assessed value) is KRW 40 billion. They want to understand how new rules on property tax (종합부동산세) could reduce their tax burden.
## What’s New: 종합부동산세 합산배제 및 과세특례 (Aggregation Exclusion & Special Treatment)
- On **9 September 2026**, the National Tax Service issued a notice urging eligible taxpayers to **file an application** between **September 16 and September 30** to get either aggregation exclusion or special taxation treatment. ([sc.nts.go.kr](https://sc.nts.go.kr/nts/na/ntt/selectNttInfo.do?bbsId=1028&mi=2201&nttSn=1354762&utm_source=openai))
- Eligibility: as of the tax base date (June 1, 2026), the property must be held by a married couple 1 home only, with no other qualifying property in another household. Domestic residency requirements also apply. ([sc.nts.go.kr](https://sc.nts.go.kr/nts/na/ntt/selectNttInfo.do?bbsId=1028&mi=2201&nttSn=1354762&utm_source=openai))
- If eligible and chosen correctly, the combined taxable property value could be treated as a single entity rather than separately. This can significantly **reduce tax liability** through joint exemptions, higher deduction amounts, or favorable marginal rates. ([sc.nts.go.kr](https://sc.nts.go.kr/nts/na/ntt/selectNttInfo.do?bbsId=1028&mi=2201&nttSn=1354762&utm_source=openai))
## Calculations: Kim Family Before vs. After Applying the Rules
| Item | Before (Separate Tax Rates) | After (Joint Application) |
|---|---|---|
| Assessment Value | KRW 40 billion (공시가격) | Same base value, but deductions and tax base functions differ. |
| Standard Deduction per spouse | Typically **KRW 9 billion each** = total KRW 18 billion | Joint owner deduction = **KRW 12 billion** total (under special treatment). Less than combined separate in some ranges, depending on property value. |
| Marginal Tax Rates Impact | Two tax rates computed separately, possible overlap and higher marginal bracket for one spouse | Joint treatment may place them in lower brackets overall. |
> Note: Under certain thresholds (e.g., 공시가격 between approx KRW 25-30 billion), joint ownership with aggregation exclusion can be vastly preferable. Beyond very high values, separate filing may be advantageous. Use online calculators (홈택스 등의 모의계산) for detailed assessment. ([sc.nts.go.kr](https://sc.nts.go.kr/nts/na/ntt/selectNttInfo.do?bbsId=1028&mi=2201&nttSn=1354762&utm_source=openai))
## Action Steps the Kim Family Should Take
1. Review the **공시가격** of their property as of June 1, 2026.
2. Confirm that no other household member owns residential property, and that they fulfill the residency and joint ownership criteria.
3. Apply online via **HomeTax / 손택스** between September 16-30, 2026.
4. Use the 종합부동산세 모의계산 (property tax estimator) to compare:
- Separate filing scenario
- Joint filing with aggregation exclusion or special treatment scenario
5. Consult a tax advisor if home valuation is high (e.g. over KRW 200 billion), because in some tiers separate may win out.
## Implications & Takeaways for Other Mid-Sized Property Owners
- These rules typically benefit **1-home households** with properties in certain value ranges.
- For multiple homes, or joint properties with family members outside of “household”—these benefits **won’t apply**.
- Key is **timing**: application window is very narrow (Sep 16–30, 2026) and considering property value as of June 1, 2026.
- Using the tax agency’s tools (모의계산) can prevent being surprised by tax bills.
## Final Thoughts
The aggregation exclusion and special treatment are powerful tools—underused due to deadlines and technical requirements. For people like the Kims, properly applying the rules can lead to tens of millions of won in annual savings. For anyone owning property, whether one or more homes, it’s worth running the numbers and meeting deadlines to optimize property tax liabilities.