Sources checked September 6, 2026. Unless stated otherwise, amounts, rates, and probabilities are illustrative assumptions. Institutional rules refer to Korea.
Before writing a ticker, write the date when the money will be needed. A housing deposit due in six months and living expenses twenty years away have different jobs. Feeling comfortable with losses also differs from being financially able to absorb them.
Explain what you own in one sentence
A stock is an ownership share in a business. Price gains and dividends can produce returns, but neither is guaranteed.1 A bond lends money to an issuer under payment promises; repayment ability and price sensitivity to interest rates require attention.2
Funds pool investors' money into underlying assets; ETFs trade on an exchange.3 Look through the wrapper. Several funds focused on the same industry may expose you to similar risks rather than provide broad diversification.4
Extend the question to your life. A company's shares, an industry fund containing it, and employment income dependent on the same industry may lean in one direction. This is a suggested household review, not a claim about any particular portfolio.
State a loss in both percentages and currency
Consider a shock scenario, not a forecast. Of KRW 10 million, KRW 6 million is in stocks and KRW 4 million in cash. If stocks alone fall 30%, the total becomes KRW 8.2 million: an 18% loss, or KRW 1.8 million. If all KRW 10 million is required in six months, remaining emotionally calm does not fill the gap.
Investor.gov connects asset allocation with time horizon and risk tolerance.4 Add practical questions: Can the deadline move? Can another income replace a loss? Concrete answers say more than confidence alone.
Diversification is not a promise of no losses. In the example, owning several different stocks still produces a loss if they all decline. The point of the scenario is to translate a market event into consequences for your plans.
Costs reduce the money left to grow
Fees and expenses remove money that could otherwise earn returns.5 Imagine KRW 10 million earning a constant 5% before costs for twenty years. In a simplified model subtracting annual costs directly from that return, a 0.2% cost gives 10 million × 1.048²⁰ ≈ KRW 25.54 million. A 1% cost gives 10 million × 1.04²⁰ ≈ KRW 21.91 million, about KRW 3.63 million less.
This assumes constant returns and costs; it is not an investment forecast. Investigate management charges, trading commissions, bid-ask spreads, currency conversion, and taxes where applicable. One advertised charge may not represent the full cost of your transaction.
If payment is demanded before the explanation is complete
Promises of high guaranteed returns, supposedly risk-free opportunities, and pressure to act immediately appear on the SEC's investment fraud warning list.6 A friend's introduction or a screenshot of profits does not cancel those signals.
Before an order, write the target amount and date, how the investment earns money, how it can lose money, total costs, and conditions for review. An empty answer is a research task. Placing the order comes afterward.
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Footnotes
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U.S. Securities and Exchange Commission, Investor.gov, Stocks — FAQs. Ownership, possible returns, and risks. ↩
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U.S. Securities and Exchange Commission, Investor.gov, Bonds — FAQs. Payment promises, credit risk, and interest rate risk. ↩
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U.S. Securities and Exchange Commission, Investor.gov, Characteristics of Mutual Funds and Exchange-Traded Funds. Pooled investment and trading structures; U.S. tax treatment is not applied to Korea. ↩
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U.S. Securities and Exchange Commission, Investor.gov, Asset Allocation and Diversification. Time horizon, risk tolerance, and the limits of narrowly focused funds. ↩ ↩2
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U.S. Securities and Exchange Commission, Investor.gov, How Fees and Expenses Affect Your Investment Portfolio, July 23, 2025. The mechanism of fee drag; this chapter uses its own assumptions and calculations. ↩
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U.S. Securities and Exchange Commission, Investor.gov, Red Flags of Investment Fraud Checklist. Guarantees, risk-free claims, and pressure to act. ↩
Sources
Related notes
This is a personal research note, not investment advice