Lee Chan-jin, governor of the Financial Supervisory Service, speaks during a meeting with reporters at the FSS headquarters in Yeongdeungpo-gu, Seoul, Monday. (Yonhap) South Korea's financial watchdog is preparing to tighten oversight of single-stock leveraged exchange-traded funds tied to Samsung Electronics and SK hynix, amid growing concerns that speculative trading is amplifying volatility in the stock market.According to industry sources Thursday, the Financial Supervisory Service will meet executives from asset management companies to discuss measures to cool the rapidly growing market. The talks are expected to focus on additional safeguards for leveraged single-stock ETFs and stronger investor protection.The FSS has stepped up scrutiny after the products' average daily turnover ratio reached 122.5 percent, with some funds recording turnover of more than 200 percent. Regulators believe trading activity has reached levels that are affecting the broader market.As domestic equities experienced sharp swings, the VKospi, which measures expected volatility in the Kospi 200, climbed as high as 95.5. Authorities believe concentrated inflows into single-stock ETFs have contributed to repeated bouts of market volatility."The FSS had limited room to intervene during the policymaking process," an FSS official said. "Now we have an opportunity to make our concerns heard."The regulator's tougher stance follows remarks by FSS Gov. Lee Chan-jin, who publicly expressed regret over the launch of single-stock leveraged ETFs."Personally, I have reflected on whether we should have stopped their launch somehow," Lee said. "I deeply regret it."Within the FSS, his comments have been interpreted as a signal to strengthen oversight of the products.Market data underscore regulators' concerns. ETF premium and discount disclosures exceeded regulatory thresholds 3,681 times in the first half of the year, equivalent to 97 percent of last year's total. Most of the increase came after single-stock ETFs debuted in May, as the products repeatedly traded at significant premiums or discounts to their net asset values.Despite the warnings, average daily trading value in single-stock ETFs has remained above 10 trillion won ($6.5 billion), highlighting persistent speculative demand.The Financial Services Commission, the country's top financial policymaker, is also reviewing additional investor protection measures, including raising the minimum investment requirement above the current 10 million won and extending mandatory investor education.