KOSPI tracks Korea's main-board equity market, while KOSPI 200 selects 200 liquid shares. Compare their weighting, formulas, uses, and risks.
The Korea Composite Stock Price Index (KOSPI) is a market-capitalization-weighted index of ordinary shares on the Korea Exchange’s main board, which is also called the KOSPI Market. It is Korea’s broad headline equity index. The KOSPI 200 is different: it selects 200 large and liquid KOSPI Market shares and uses free-float-adjusted market capitalization for an investable blue-chip benchmark.
100.100.The similar names create a basic ambiguity:
An investor does not buy “the KOSPI” directly. A fund, future, option, note, or other instrument may reference a particular KOSPI series, but that product has its own costs, liquidity, tax treatment, tracking behavior, and risks.
The simplified KOSPI formula compares current adjusted market capitalization with adjusted base market capitalization:
where:
The base date is January 4, 1980, and the base index value is 100. KRX began publishing the current market-cap-based KOSPI in 1983 using that earlier base date.
The base market value is adjusted for qualifying events so that new listings, delistings, rights issues, mergers, and other non-price changes do not create misleading jumps. Therefore, a KOSPI level of 2,500 should not be interpreted as proof that a fixed portfolio or the Korean economy is exactly 25 times larger than in 1980.
KOSPI 200 uses free-float-adjusted market capitalization. A simplified constituent value is:
where (F_i) is the free-float factor. The constituent weight is:
Strategic, controlling, government, treasury, or other non-floating holdings can reduce the shares used for KOSPI 200 weighting under the methodology. Free-float adjustment is intended to make weights more investable; it does not guarantee that all adjusted shares can trade immediately without market impact.
Assume three companies are eligible for both simplified indexes:
| Company | Full market cap | Free-float factor | Broad KOSPI-style weight | KOSPI 200-style free-float weight |
|---|---|---|---|---|
| A | KRW 700 trillion | 35% | 50.00% | 32.89% |
| B | KRW 400 trillion | 80% | 28.57% | 42.95% |
| C | KRW 300 trillion | 60% | 21.43% | 24.16% |
| Total | KRW 1,400 trillion | 100% | 100% |
Company A dominates the full-market-cap calculation, but Company B has the largest free-float-adjusted weight because a much larger proportion of its shares is treated as publicly investable.
If A returns 2%, B returns -1%, and C returns 3%, the simplified returns are:
This example isolates the weighting difference. The real indexes have different constituent universes and maintenance rules, and the figures are not forecasts.
| Feature | KOSPI | KOSPI 200 |
|---|---|---|
| Main role | Broad KOSPI Market headline index | Selected blue-chip and derivatives benchmark |
| Constituents | Eligible ordinary shares across the main board | 200 selected common stocks |
| Weighting | Adjusted full market capitalization | Free-float-adjusted market capitalization |
| Base date and value | January 4, 1980 = 100 | January 3, 1990 = 100 |
| Membership changes | Listings, delistings, and market events | Scheduled reviews plus special changes |
| Typical linked uses | Market reporting and broad benchmarking | Futures, options, ETPs, structured products, and funds |
KOSPI 200 was launched in June 1994 and was designed as an underlying index for equity derivatives. KRX selects constituents using size, trading activity, sector representation, and eligibility rules rather than simply taking the 200 largest companies on one date.
Public Korean regulatory guidance describes scheduled KOSPI 200 reconstitution in June and December, with special changes possible for delistings, mergers, and other events. Analysts should verify the current KRX methodology and review notice before predicting additions or deletions because thresholds and implementation details can change.
| Feature | KOSPI Market | KOSDAQ |
|---|---|---|
| Market role | Korea’s main board | Separate market associated with growth-oriented and smaller issuers |
| Headline index | KOSPI | KOSDAQ Composite |
| Selected derivatives benchmark | KOSPI 200 | KOSDAQ 150 |
| Index base | KOSPI: January 4, 1980 = 100 | KOSDAQ Composite uses a separate base and scale |
KOSDAQ stocks are not automatically part of KOSPI merely because both markets are operated by KRX. A company can transfer markets under applicable listing rules, but the market and index memberships remain distinct concepts.
The commonly quoted KOSPI and KOSPI 200 levels are price indexes. KRX also publishes total-return variants:
| Series type | Price changes | Cash-distribution treatment | Main analytical use |
|---|---|---|---|
| Price index | Included | Excluded from ordinary reinvestment | Headline market movement |
| Total return | Included | Cash distributions reinvested under KRX rules | Dividend-inclusive comparison |
| Net total return | Included | Reinvestment after specified tax assumptions, where available | Cross-border benchmarking |
If KOSPI rises from 3,000 to 3,150, the price return is:
Do not add an annual dividend yield mechanically to that result. Use the official total-return series because ex-dates, constituent changes, reinvestment timing, and index rules affect the calculation.
KOSPI indexes are calculated in Korean won. For an investor measuring returns in another currency:
If the KRW index gains 10% while the won loses 6% against the home currency:
This simplified calculation excludes fees, taxes, hedging, tracking differences, and cash flows.
Neither index is a complete measure of Korea’s economy. Large exporters, valuation changes, exchange rates, and a few heavily weighted companies can move the indexes differently from household income, employment, private businesses, or gross domestic product.
This article is educational and does not recommend an index fund, derivative, security, currency position, or allocation.