How do you invest in the KOSPI?

Index funds and ETFs tracking the KOSPI are the standard route. When comparing them, three things decide your outcome: the expense ratio, the tracking difference against the index, and the fund's domicile, which determines withholding tax on dividends.

Investors outside South Korea should also account for currency: an unhedged fund delivers the index return plus or minus the exchange rate.

Also check what the index actually holds before assuming it is diversified. Several major indices are dominated by a handful of very large companies, so the top ten weights matter far more than the total number of constituents.