Offshore leveraged bets on Samsung and SK Hynix grew more than twentyfold in six months

Concentration alone gives the Kospi a single dependency. Samsung Electronics and SK Hynix are close to half the market capitalisation of the index ^[2]. A 10% same-day fall in the pair takes roughly five percentage points out of the index by weight alone, before any spillover ^[1].

The offshore products add a second step. Several of them used leverage of up to four times while opening and closing positions connected with global memory-chip companies ^[5]. At four times, a 10% single-day drop in the underlying is a 40% loss in the product that day ^[2]. Daily rebalancing then has the operator buying into rising markets and selling during declines ^[6]. The central bank's warning is about that push, with rapid adjustments by large products reinforcing price movements and transmitting volatility between overseas trading venues and Seoul ^[7].

The cash, meanwhile, is going out on the strength of the current cycle. Samsung and SK Hynix have announced 2026 shareholder-return plans totalling more than 130 trillion won, which Reuters reported are supported by cash generated during the AI-related memory boom ^[16]. Investor reaction was restrained, with some shareholders continuing to seek governance changes and share repurchases ^[17], and analysts cited by Reuters described the earnings gains as dependent on a cyclical industry ^[18].

Beyond the index, the dependence is on the record. Semiconductors were more than 40% of South Korean merchandise exports during some months of 2026, according to customs and central-bank data ^[13], and real GDP grew 0.6% in the second quarter ^[14]. The September report set that expansion beside rising asset prices, household borrowing and changing conditions in overseas financial markets ^[3].

I would price the rebalancing. A slowdown in accelerator orders shows up in the earnings of the three main advanced-memory suppliers over quarters that analysts can model ^[19]. Forced selling by a four-times product shows up in the price the same afternoon ^[6]. The growth published on the Hong Kong products is a multiple, and the reported account does not include their total value, so the case turns on relative size. If those products are small against daily turnover in the two stocks, this is prudential housekeeping. The second version has already happened in Korea: the planned domestic restrictions followed sharp changes in Korean technology stocks and forced adjustments by leveraged funds ^[11].