Overseas Stock Capital Gains Filing, Why 'All Trades and FX Rates' Are Enough?

There is one clear rule: collect 'all trade records after sale and FX rate documents'.

This is because the first box on the form records the aggregated gains and losses.

Retail investor question:

"Do I need to file separately for each broker?"

If within the same tax year, you combine gains and losses by trade, although source documents must be verified per account and per broker.

Where do you enter the 'netting' result first?

Tax year total

Sum of gains and losses by trade

You only need to enter the net sum, and then attach the calculation supporting sheet.

Netting means combining gains and losses subject to the same tax base to calculate tax.

What do you need to prepare?

→ 1. Trade statement: prepare buy/sell dates, quantities, and KRW-converted amounts.

→ 2. FX evidence: prepare documents supporting the trade date rate or the National Tax Service designated rate.

→ 3. Fee and tax receipts: trading costs are deducted when calculating capital gains.

Capital gain means the proceeds from sale minus purchase cost, fees, and currency conversion costs.

Example 1, single account with only gains

Step 1: Calculate total proceeds and total acquisition cost from the trade statement.

Step 2: Enter taxable base as total proceeds − total acquisition cost − fees.

Step 3: Attach FX evidence files and record the total amount on the return.

Example 2, mixed gains and losses across multiple brokers/accounts

Step 1: Collect trade statements from all brokers.

Step 2: Calculate gains and losses per broker, then sum within the year.

Step 3: Enter the summed result in the return total box and attach supporting documents grouped by company.

Example 3, losses due to FX losses or fees

Step 1: Include FX losses and conversion fees in the trading profit and loss calculation.

Step 2: If FX losses make the total negative, mark the netting result as a 'deficit'.

Step 3: Note and submit the reasons for the deficit and the FX rate evidence separately.

Frequent mistakes during filing

• Failing to check the trade date FX leads to double counting in many cases.

• Omitting fees inflates the taxable base.

• Submitting only the total without a broker-by-broker summary triggers a document request from the tax office.

So, where do you start?

→ 1. Today: download this year’s trade statements and FX evidence files.

→ 2. Next: organize acquisition and sale prices by broker and sum them in Excel.

→ 3. Final check: confirm supporting items with the National Tax Service or your tax agent before filing, and verify the latest standards with them.

Please use this as reference only.

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※ This article is for information only and is not investment advice.

※ Investment decisions and responsibilities lie with the investor.

※ Figures are as of the time of writing and may change.

This article is for information only and is not investment advice.