Preying on Leveraged ETFs

2026-08-04

AI Summary

This study addresses the extreme market volatility observed in Korea in 2026, which stemmed from manipulative trading exploiting the closing rebalancing mechanism of leveraged ETFs. Arbitrageurs executed a closed-loop strategy—establishing positions in advance, inflating order flow, and then reversing trades—to extract profits at the expense of retail investors, who incurred losses of approximately 4 trillion KRW and witnessed an annualized volatility surge of 47 percentage points over eight weeks. The paper provides the first quantitative characterization of this manipulation channel, integrating event studies, control-group analysis, and high-frequency data modeling to demonstrate how the rebalancing reference price critically amplifies market volatility and facilitates wealth transfer. As a novel remedy, the authors propose replacing the single-point closing price with a multi-point average as the rebalancing benchmark, which simulations show can reduce artificial volatility by nearly half and substantially enhance market resilience.

Abstract

We argue that the extreme volatility of the Korean market in 2026 was driven by arbitrageurs preying on the closing rebalance of leveraged exchange-traded funds (LETFs). An LETF must trade in the direction of the day's move at a close that also measures it, so its demand rises in price, and arbitrageurs buying ahead of it enlarge the order by trading at the print, then unload into what they manufactured. As predicted, pre-open U.S. news is reversed one day later in Samsung Electronics and SK Hynix once their products list, and in no control group. At measured parameters the loop added forty-seven percentage points of annualized volatility and transferred KRW 4 trillion from retail holders in eight weeks. Dispersing the rebalance through the session, Korea's chosen remedy, moves the order but not the reference that sizes it and can raise the toll. Changing the reference works instead: an average of two prints halves what displacing either can manufacture.

Problem

• leveraged ETFs
• arbitrage
• market volatility
• rebalance
• retail investors

Innovation

• leveraged ETFs
• closing rebalance
• arbitrage loop
• reference price design
• market volatility