One reason is that the basis value of the contracts are so small - like trading 20 nickels vs 1 silver dollar. Imagine reducing the size of ES options and commissions by 10 - trading volume goes up exponentially. Also, ticks on the options are miniscule. Bottom line, the contracts are simply well constructed to facilitate volume. A second reason is that Korea is extremely hardwired to the internet, and to online trading. (Makes US almost look third world, to be frank.) It is prevalent to a degree that would be shocking to most westerners who haven't been exposed to that phenomenon. Taiwan is similar, but not as prevalent as online trading is relatively new there and locally-listed futures are only a few years old.
I would also add that commissions on options are tied to the option price (?) - it is not a per-contract charge. Thus buy an option for 0.35 and pay half the commission than if you pay 0.70 contract closer to the money (or longer horizon.) This makes trading the deep OTM KOSPI contracts more attractive than trading similar contracts on other indices. That's the way I think it works ... happy to stand corrected. Has IB come out with commission rates yet? This could be a whole new animal for them. IMO KOSPI futures/options are the best-constructed in the world, except that they are not traded out-of-hours, which is essential.
i traded them for awhile in korea. a rollercoaster, powerful moves, liquid. fastest and easiest way to make/lose money in the markets there. no taxes for korean citizens. i play currencies now and the kospi 200 options is a similar game.
To BlueHorseshoe: IB commissions are published at http://www.interactivebrokers.com/en/accounts/fees/commissionStockIndexOptions.php?ib_entity=llc 0.2% of option value Minimum per order is KRW 1,000 Example: 10 Contracts @ KRW 0.75 Premium (KRW 100,000 Multiplier) = KRW 1,500 It is less then $1.5