South Korea is moving to bar investors under 19 from margin trading, tightening safeguards around leveraged investing as regulators increasingly focus on the risks that rising borrowing costs and market leverage pose to financial markets. The changes could affect U.S. investors and global financial firms with exposure to South Korea’s brokerage and capital-markets industry by reshaping how securities firms manage retail leverage and investor-protection standards.
Financial authorities are discussing measures that would explicitly prohibit minors from using margin accounts, rather than leaving the issue largely to individual securities firms. Regulators are expected to push the industry toward a uniform restriction as early as next month.
The initiative reflects broader concerns over the rapid expansion of leveraged retail investing in South Korea, where securities firms have increasingly tightened controls on high-risk products. Regulators have also warned about practices involving the sale or recommendation of leveraged investments and margin transactions to minors.
Outstanding margin balances held by investors under 20 at South Korea’s 10 largest securities firms rose to about $143 million at the end of June from roughly $86 million at the end of January, an increase of about 67%, according to data submitted to lawmaker Kim Sang-hoon’s office.
The shift is already being implemented across the brokerage industry. KB Securities stopped accepting new applications for margin trading by minors on July 25 and blocked the practice for existing minor accounts on Aug. 31. Samsung Securities followed on Sept. 4, while Shinhan Securities plans to impose a full restriction on Oct. 12.
Regulators expect the rest of the industry to follow by early October, allowing time for brokerages to modify their trading systems and disable margin-trading functions on accounts held by minors.
“Industry participants agree that margin trading by minors is not desirable and are voluntarily suspending the practice,” a financial-authority official said. “But that alone may not be sufficient, so we are discussing ways to impose an explicit restriction through exchange rules and industry-association regulations.”
The regulatory push comes as South Korea’s financial authorities broaden their focus from investor protection to the systemic effects of leverage.
The Financial Services Commission plans to hold a market-monitoring meeting on Oct. 1 with the Financial Supervisory Service and financial-market experts to assess risks in stocks, foreign exchange and other parts of the capital markets as interest rates rise.
For investors, the more consequential issue is the resilience of South Korea’s retail-investment boom as financing costs increase. The Federal Reserve raised interest rates last week, while expectations of a Bank of Korea rate increase have strengthened, potentially raising funding costs for investors using borrowed money.
Retail leverage has remained firm even as cash parked in brokerage accounts has declined.
Investor deposits fell to about $69.6 billion on Sept. 17 from roughly $76.9 billion a week earlier. Over the same period, credit-financing balances at securities firms increased to about $23.6 billion from $23.1 billion.
Credit balances had climbed above $27 billion in June during a stock-market rally before falling to about $19 billion in early August. They have since begun to rise again.
The divergence between declining investor cash and rising borrowed-money balances is drawing attention from regulators because leverage can amplify both gains and losses when markets turn volatile.
Short-term margin receivables, meanwhile, remained broadly stable at about $724 million between Sept. 10 and Sept. 17.
Financial Services Commission Chairman Lee Eog-won said Sept. 18 that regulators would place greater emphasis on long-term investing rather than short-term trading financed with debt.
“We will closely manage leverage in the stock market, including margin financing,” Lee said, adding that authorities would further refine market-stabilization and emergency measures designed to contain volatility.
For global investors, the measures point to a broader evolution in South Korea’s retail-capital-market framework: securities firms are moving toward tighter controls on leveraged products while regulators prepare more explicit industrywide standards.
The immediate effect is likely to be concentrated in retail brokerage practices, but the policy direction also underscores authorities’ growing concern that leverage could magnify market stress during periods of higher interest rates and sharp asset-price moves.
