APT · WORKED CASE 03

Buy versus jeonse: compare the financing layer honestly

A deliberately limited comparison showing why principal repayment and interest-only deposit financing should not be labelled as equivalent monthly costs.

INPUT LEDGER

What is known, entered, or assumed.

InputValueOrigin
Purchase case₩900M price; ₩540M loanIllustrative scenario
Jeonse case₩600M deposit; ₩360M loanIllustrative scenario
Rate4.2%Held constant for illustration
Purchase term30-year equal paymentUser assumption

REPRODUCIBLE CALCULATION

Follow the intermediate result.

01

Purchase scheduled payment

Formula or rule: ₩540M, 4.2%, 360 payments

Result: About ₩2,640,693 per month

02

Jeonse interest layer

Formula or rule: ₩360M × 4.2% ÷ 12

Result: About ₩1,260,000 per month

03

Visible cash-flow gap

Formula or rule: ₩2,640,693 − ₩1,260,000

Result: About ₩1,380,693 per month

04

Classification check

Formula or rule: Purchase payment = principal + interest

Result: Not equivalent to interest-only cost

DECISION READING

What the result means.

The ₩1.38M gap is not a verdict that jeonse is cheaper: part of the purchase payment builds equity. A useful tool must show cash outflow, interest cost, principal change, capital tied up, and deposit risk as separate rows.

SENSITIVITY

What could change the answer.

  • Changing the two loan amounts can reverse the visible cash-flow gap.
  • Deposit return risk and guarantees matter to the jeonse case.
  • Acquisition tax, ownership costs, and expected holding period matter to the purchase case.

BOUNDARIES

What this case does not prove.

  • The jeonse line is an interest-layer illustration, not a quoted loan product.
  • No property appreciation, rent change, or investment return is forecast.
  • Eligibility and legal protections require household-specific verification.

OFFICIAL SOURCES

Where factual context is verified.

RELATED APT CASES

Change one assumption and compare again.

Each case keeps inputs, arithmetic, evidence, and uncertainty in separate layers.

01 · From an ₩800M price to a monthly housing burden02 · How 3.5% versus 5.0% changes the same loan