Samsung Electronics and SK Hynix recorded only modest declines on September 10 despite an expected sell-off of up to 1.8 trillion Korean won linked to the Korea Exchange (KRX) Semiconductor Index rebalancing. The changes affected listed index products, including ETFs and ETNs, and coincided with the expiration of futures and options. SK Hynix’s index weight fell from 38.01% to 20.00%, while Samsung Electronics’ declined from 22.06% to 20.00%, reflecting a 20.00% individual-stock cap. ETFs tied to the index hold about 8 trillion Korean won in assets. Actual selling pressure was absorbed by futures-linked arbitrage buying and financial institutions’ net purchases of about 1.8 trillion Korean won. SK Hynix fell 0.16% and Samsung Electronics declined 0.19%, both outperforming the KOSPI’s 0.98% drop. Passive funds also shifted allocations toward semiconductor materials, parts and equipment companies, lifting the weights of Hanmi Semiconductor, Jusung Engineering, Wonik IPS, EO Technics, HPSP, Leeno Industrial and DB HiTek.