Why Korea's new leveraged ETFs are under scrutiny

South Korea's financial regulator has launched a fact-finding review of newly listed single-stock leveraged exchange-traded funds tied to Samsung Electronics and SK hynix after signs of unusually heavy trading raised questions about how the products generated more than 10 trillion won ($6.65 billion) in turnover on their first day.

According to industry sources Monday, the Financial Supervisory Service recently contacted several brokerages acting as liquidity providers, or LPs, and asset manager ...