Mirae Asset Securities raised margin requirements for some stocks to respond to increased volatility in South Korea's stock market. The move aims to cut investment risks from excessive leveraged trading and strengthen protection of customer assets.

Mirae Asset Securities said on Wednesday it adjusted margin requirements for some domestic stocks to respond to rising volatility in the local stock market.

The adjustment follows a sharp increase in price volatility in the market and in individual stocks over a short period, which has raised customer investment risks. Mirae Asset Securities decided to change part of its margin requirement framework for domestic stocks to provide a stable trading environment.

South Korea's stock market has been showing high volatility as market capitalisation becomes increasingly concentrated in large semiconductor stocks and assets in leveraged exchange-traded funds (ETFs) rise. It judged that short-term price swings have also widened, raising investment risks compared with the past.

In particular, leveraged products can generate additional selling pressure when underlying asset prices fall, which can amplify shocks to the market.

Outstanding unpaid balances in brokerage trading in the domestic stock market are also rising. From January 2025 to March 2026, the monthly average was about 967.4 billion won, but the pace of increases accelerated after March. The figure stood at 1.56 trillion won in June 2026, up 61.5 percent from the average over the period.

Mirae Asset Securities said it adjusted margin requirements pre-emptively after determining that the existing framework alone may not sufficiently mitigate fast-changing market risks.

Under the change, stocks that had been subject to margin requirements of 20 percent and 30 percent will be raised uniformly to 40 percent. Stocks subject to 40 percent and 100 percent margin requirements will remain unchanged. The revised requirements took effect on Tuesday.

It will also temporarily suspend new applications and maturity extensions for its tailored margin service. New applications will be suspended from Tuesday and maturity extensions from Thursday.

A Mirae Asset Securities official said, "This margin requirement adjustment is a risk management measure to protect customer assets from unexpected shocks," adding, "We will continue to do our best so that investors can invest in a stable environment."