A report from JPMorgan's Asia Pacific Equity Derivatives Strategy team points out a substantial change in the volatility structure of the South Korean market in September: the increase in the volume of listed options selling outweighed the residual short Gamma pressure from leveraged ETFs, resulting in traders turning net long on Gamma positions in South Korean stocks to approximately $430 million, the longest Gamma position in the past year. The report argues that this signifies a shift in the market from a one-sided Gamma mechanism driven by leveraged ETFs to a more balanced two-way liquidity environment.
Skewing provides another signal: the skewness of 3-month 40d–20d call options on the KOSPI2 index has turned deeply negative to -2%, a five-year low, with the bullish skewness of Samsung Electronics and SK Hynix also near historical lows. Meanwhile, the convexity of 2-month options on the two chip stocks rose to 7%, a record high—implied volatility on both sides has been significantly repriced.
