Korean Retail Investors Start Leveraging Again! Margin Balances Exceed 30 Trillion Won as Regulators Issue Warnings

The retail leverage boom in South Korea has returned, and the patience of regulators is running out. After a series of restriction measures targeting single-stock leveraged ETFs yielded limited results, the Financial Supervisory Service (FSS) has now focused on the more fundamental and larger margin balance, warning brokerage firms that if industry self-regulation falls short, additional supervisory tools will be implemented.

On October 27, Seo Jae-wan, Vice President of the FSS in charge of the capital market, convened Chief Risk Officers from ten major brokerages across South Korea for a meeting in Yeouido, Seoul. At the meeting, he clearly expressed "disappointment" at the effectiveness of industry self-regulation since the CRO meeting in June. According to the Korea Financial Investment Association, the margin balance reached a peak of KRW 38.63 trillion on June 24 before declining, but it still stood at KRW 30.15 trillion as of the 23rd of this month, higher than the KRW 27.42 trillion at the beginning of the year.

The regulators warned that if the margin balance continues excessive expansion, a sharp drop in stock prices could trigger a chain reaction of forced liquidations, causing systemic shocks to the market. For the market, the core signal of this statement is that South Korea’s regulators are systematically tightening their overall tolerance for retail leverage, with policy boundaries extending from the product side to the funding side.

KRW 30 trillion is not the absolute historical high, but its persistence is at the heart of regulatory concern. Since the start of the year, regulatory authorities have tightened restrictions on leveraged ETFs layer by layer, but the total volume of retail margin trading has not declined; rather, it has stabilized at a higher level. This indicates that funds have shifted from leveraged ETFs to direct margin channels under regulatory pressure, rather than truly exiting the market.

Seo Jae-wan emphasized in the meeting that if the margin balance expands excessively, a sharp decline in share prices could cause a chain reaction of forced liquidations, damaging market confidence. He stressed the industry must proactively establish and implement effective preemptive risk management measures. This is the clearest public pressure from regulators since June, and the wording "additional supervisory tools" is seen externally as a clear warning of a policy upgrade.

The FSS opting to issue a warning to brokerages instead of directly implementing rules shows that regulation is still in the "pressure—observe" stage. However, upgrading the wording from "attention" to "warning" means the policy toolbox has been opened, and subsequent actions will depend on whether brokerages proactively tighten margin standards.

In recent months, South Korean regulators have pursued a highly consistent approach in governing retail leverage. First, they raised the minimum pre-deposit requirement for single-stock leveraged ETFs from KRW 10 million to KRW 30 million, directly causing the number of related trading accounts to plummet from around 100,000 to 10,000 and reducing trading volumes by over 60%. They subsequently suspended new listings for single-stock leveraged ETFs and, since August 19, enforced a mandatory 5-day simulated trading period. Regulators have also pushed for legal amendments to enable cutting leverage multiples from a fixed 2x to 1.5x or 1x in emergencies.

The rebalancing of leveraged ETFs linked to SK hynix and Samsung Electronics previously caused sharp intraday volatility in the KOSPI, directly prompting the accelerated tightening from regulators. Yet, after these measures were implemented, retail leverage demand did not disappear but instead migrated to more traditional margin channels. This latest warning from the FSS essentially acknowledges that regulation targeting ETFs only solved part of the problem.

Brokerages attending the meeting recognized the need to strengthen margin balance controls and pledged to actively cooperate with regulatory requirements. Reportedly, major brokerages have implemented several self-discipline measures since this month: from October 1, 10 large brokerages voluntarily capped their total credit financing, including margin trading, at 90% of net assets, below the legal maximum of 100%. From the 19th, they began reducing exposures in stocks where the margin balance exceeded 15% of each firm's total margin lending.

Some brokerages have lowered the base credit line for stocks with a high concentration of margin lending from KRW 3 million to KRW 2 million, or narrowed credit limits by downgrading the internal ratings of certain stocks. Others have established real-time monitoring systems for margin balances and intraday price fluctuations, immediately triggering rating downgrades or credit restrictions if warning signals emerge.

The FSS stated it will work jointly with the Korea Financial Investment Association to ensure that controls on the total volume of margin lending and limits on exposures to individual stocks are effectively implemented.

Margin balance is an important source of income for Korean retail brokerage businesses. If regulators further impose additional restrictions—such as raising the initial margin ratio, tightening the maintenance margin requirement, or capping the growth of margin balances—it will directly curb the buying power of retail investors and compress brokerage interest income. For the stock market, retail margin trading is a crucial component of KOSPI liquidity. South Korean retail investors have already recorded historic net selling on the KOSPI, and if further restrictions are imposed on margin channels, the market will lose a key source of marginal buying, potentially amplifying index volatility as the shock from the leveraged ETF rebalancing has yet to be fully absorbed.