South Korea’s stock market has been whipsawed by extreme swings in recent weeks, with analysts increasingly pointing to the explosive growth of exchange-traded funds as a key driver of the volatility.
Massive inflows into ETFs – combined with leveraged bets and algorithmic trading – have amplified market moves in both directions, turning routine shifts in sentiment into outsized gains and losses.
The dynamic was on full display this week when the benchmark Kospi staged one of its sharpest rebounds on record, surging nearly 10% in a single session after suffering the worst two-day selloff in its history amid geopolitical tensions linked to the US-Iran conflict.
The dramatic reversal highlighted how quickly markets can snap back when systematic and passive flows dominate trading.
ETF BOOM FUELS MARKET SWINGS
Trading in ETFs has exploded in South Korea this year.
According to data from the Korea Exchange on Thursday, average daily ETF turnover has climbed above 34 trillion won ($23 billion) in March, compared with about 19.2 trillion won in February and 6.6 trillion won in December, marking a nearly five-fold increase in a matter of months.
The surge reflects a flood of money chasing the country’s strong equity rally earlier this year, as investors sought cheaper and easier exposure to high-profile stocks through ETFs rather than buying individual shares.
The country’s benchmark Kospi index has become the world’s best-performing stock index this year, with a rise of nearly 50% in the first two months after skyrocketing more than 90% last year.
But the influx of capital in the ETF market has also created what industry officials describe as a bottleneck effect, with large inflows chasing a relatively narrow set of underlying assets.
LEVERAGED FUNDS MAGNIFY VOLATILITY
Leveraged ETFs have played a particularly powerful role in amplifying market swings, market analysts said.
These products aim to deliver twice the daily return of an index or a stock, forcing managers to rebalance positions mechanically through futures and cash equities.
During sharp market declines, the funds often unload large volumes of stocks late in the session to maintain their leverage targets, exacerbating losses across the broader market.
“This month’s unprecedented volatility was partly driven by the expansion of leveraged ETF assets, which increased demand for end-of-day rebalancing trades,” said Kim Ji-hyun, an analyst at Daol Investment & Securities Co.
ALGORITHMIC TRADERS JOIN THE SELLOFF
Algorithm-driven hedge funds have added to the pressure.
Commodity trading adviser, or CTA, funds, which trade derivatives based on systematic signals, have increased their selling as markets turned volatile.
JPMorgan said volatility-sensitive investors such as CTAs were among the main forces behind foreign investors’ heavy selling in March.
Because many CTA strategies follow momentum signals, they often increase short exposure or reduce long positions when markets weaken, which can accelerate declines once selling pressure begins.
DIVERSIFICATION ILLUSION
The rapid growth of ETFs has also raised questions about whether they truly offer diversification in South Korea’s equity market.
Even funds marketed as diversified, such as dividend or value ETFs, often carry large weightings in the country’s biggest companies.
“Many investors think they’re diversifying across ETFs, but a large number of these products still hold significant stakes in the same large-cap names, particularly Samsung Electronics and SK Hynix,” said an ETF-trading industry official.
With the Korean semiconductor giants dominating the Kospi’s market capitalization, concentrated ETF flows can funnel capital into a narrow group of technology stocks, making the broader market more vulnerable to abrupt swings when sentiment shifts, the official added.
The Kospi fell more than 2% in early trading on Friday after US markets retreated overnight on renewed concerns that oil prices could surge amid the ongoing US-Iran conflict.
