South Korea's financial authorities suspended the rule that makes brokerages keep collateral worth at least 140% of a margin loan, giving firms three months from Monday, Nov. 9, to lower that threshold or put off forced sales. The decision came on Friday, when the Kospi fell more than 8% after the open, set off a 20-minute marketwide halt and closed down 6.02% at 5,059.69, according to Yonhap.

As an emergency brake, the waiver is defensible. As policy, it is becoming a reflex. Seoul should treat this suspension as the last of its kind, decline to extend it in February, and use the three months to shrink the retail leverage that made the brake necessary.

What the Waiver Does, and What It Cannot

The measure came out of an emergency meeting chaired by Deputy Prime Minister and Finance Minister Lee Hyoung-il, with the heads of the Financial Services Commission, the Financial Supervisory Service and a Bank of Korea deputy governor, Aju Press reported. It is not a ban on forced selling and does not raise borrowing limits. Each brokerage decides how much slack to give. Forced sales of unpaid stock purchases, where an investor fails to settle a trade, are outside its scope.

The case for acting was real. Margin-loan liquidations at the 10 largest securities firms rose from 56.51 billion won in January to 393.51 billion won in June, according to data submitted to lawmaker Kim Sang-hoon and cited by Aju Press. Liquidations of unpaid purchases reached 5.15 trillion won in the first 10 months of 2026, about four times the level a year earlier, Korea Financial Investment Association (KOFIA) data show. When falling prices trigger sales that push prices lower, a pause can stop a mechanical spiral. On Friday the index recovered about a third of its losses after the late-morning announcement, Aju Press reported, with institutions doing most of the buying.

That is the strongest argument for the waiver, and it deserves weight. Forced selling at the open of a panicked session transfers losses to the most exposed investors at the worst prices, and it can turn a sharp drop into a disorderly one. Officials also argued that Korean shares had overreacted to outside events, citing growth forecasts in the mid-3% range and exports heading for $1 trillion this year.

But the waiver delays the reckoning; it does not cancel it. A borrower spared on Monday still owes the loan. If prices keep falling, the margin call that arrives in January is larger, and the brokerage that held off carries more of the risk. Seoul has tested this before. It suspended the same collateral requirement from July 4 through Sept. 30, 2022, according to the Financial Services Commission. The Kospi still hit its low for that year in September and finished 2022 down 24.9%, Aju Press reported.

Leverage Is the Problem to Fix

The numbers going into Friday were not reassuring. Outstanding margin loans were 28.64 trillion won on Nov. 4, down 25.9% from a June 24 peak of 38.63 trillion won, according to KOFIA data cited by Aju Press. Investor deposits fell faster, by 34.7% to 89.23 trillion won, so margin debt rose to 32.1% of deposits from 28.3%. Borrowing has come down, but the cash cushion behind it has thinned more.

Concentration makes it worse. Friday's fall was led by SK hynix, down 10.44%, and Samsung Electronics, down 6.35%, Yonhap reported. A retail book built on borrowed money and two memory stocks can lose its collateral buffer in one session, as Capital Times explained on Friday. Each waiver also sends a signal. If borrowers learn that the 140% line is suspended whenever it starts to bite, the line stops shaping behavior before the crisis, which is the only time it can.

This board has argued that Korea's pension fund should not be turned into a backstop for the Kospi. The same logic applies here. Rules that bend in every sell-off end up subsidizing the leverage that causes the next one.

How to Use the Three Months

First, let the waiver expire on schedule in early February. Any extension should require a published finding that market functioning, not index levels, is still impaired.

Second, require each brokerage to disclose how it is using the waiver: the threshold it applies, how long it delays sales and how many accounts benefit. Borrowers cannot manage a risk they cannot see, and supervisors cannot judge whether firms are taking on losses they cannot absorb.

Third, start work on collateral rules that reflect concentration. A margin account holding a single volatile chip stock is riskier than one holding a broad index fund, and the required buffer should say so. Tighter treatment of unpaid purchases, which the waiver does not touch and which have quadrupled this year, belongs in the same review.

Authorities said they would prepare more stabilization measures if volatility rises. The better test of policy is what happens to margin debt before then. The next KOFIA figures, covering Thursday and Friday, will show how much forced selling the rout produced before the relief began.

This editorial is general commentary, not financial advice.