KOS Stock Plunges 77% on HOSE as Chairman Margin Calls Trigger 19 Floor Sessions

Overview

KOS, the HOSE-listed real estate developer Kosy, has lost nearly 77% of its market value in just over a month, closing at VND 7,760 on 15 October 2026 after a 19th consecutive floor-price session. The decline has been driven by forced margin-call selling by Chairman Nguyen Viet Cuong and entities linked to him, with the company’s market capitalization falling to about VND 1,680 billion.

Key Facts

• KOS closed at VND 7,760 per share on 15 October 2026, down the full 6.95% daily limit and the 19th straight floor session.
• Market capitalization has fallen to roughly VND 1,680 billion, a loss of more than VND 5,500 billion over the period.
• Only 50,700 KOS shares matched on 15 October, while 76 million shares (about 35% of the company’s shares) sat at the floor with no offsetting demand.
• Chairman Nguyen Viet Cuong was margin-called on 560,854 KOS shares between 7 and 13 October 2026, cutting his holding to 71.81 million shares, or 33.17% of charter capital.
• Kosy Real Estate Investment Co. Ltd. was forced to sell 754,900 KOS shares from 9 to 15 October 2026, reducing its stake from 4.605% to 4.26%.
• Leo Regulus Investment JSC was margin-called on 4,732 KOS shares, trimming its holding from 10.253% to 10.251%.
• Combined, the Chairman and the two related entities were forced to sell more than 1.32 million KOS shares in early October 2026.

What Happened

Kosy’s shares have been locked in a rare sequence of floor-price sessions on the Ho Chi Minh Stock Exchange. According to the company’s disclosures, the selling pressure stems from margin calls at brokerage firms rather than open-market decisions by the shareholders. On 15 October 2026, two organizations connected to Chairman Nguyen Viet Cuong simultaneously reported forced sales, each citing securities-company liquidation as the reason for the ownership change.

Kosy Real Estate Investment Co. Ltd., where Cuong serves as Chairman of the Members’ Council and Vice Chairwoman Nguyen Thi Hang is a capital contributor, reported a forced sale of 754,900 KOS shares between 9 and 15 October 2026 via order matching. Its holding fell to 9,214,800 shares, or 4.26% of charter capital. Leo Regulus Investment JSC, chaired by Cuong with Hang on its board, was forced to sell 4,732 shares, leaving it with 22,190,768 shares, or 10.251%. Separately, Cuong himself was margin-called on 560,854 shares between 7 and 13 October 2026. The filings do not disclose the value of the forced sales.

Market Context

KOS trades on HOSE in the real estate sector, a segment that has faced persistent funding pressure as corporate bond maturities and tight credit conditions weigh on developers. The stock’s collapse stands out even against that backdrop: 19 consecutive floor sessions with negligible matching volume indicate a near-total absence of buyers rather than ordinary profit-taking. The 76 million shares queued at the floor on 15 October represent roughly 35% of the company’s share count, a supply overhang that has so far overwhelmed any dip-buying interest.

Strategic Significance

The core issue for long-term investors is control and balance-sheet resilience, not the share price alone. Chairman Nguyen Viet Cuong still holds 33.17% of KOS after the forced sales, and the related entities retain meaningful stakes, but the margin-call cascade signals that the controlling group’s holdings were pledged against borrowings. Each further liquidation weakens the ownership base and can trigger additional selling if prices stay depressed. For a real estate developer, a falling share price also narrows access to equity financing and can complicate asset sales or project-level fundraising, creating a feedback loop between the stock and the operating business.

What to Watch

• Further disclosure filings from Cuong, Kosy Real Estate Investment, and Leo Regulus on additional margin-call sales.
• Whether the 76 million shares queued at the floor clear, and at what price, as a signal of genuine demand.
• Kosy’s next financial statements for cash position, debt maturities, and any asset-sale progress.
• Any HOSE or State Securities Commission inquiry into the consecutive floor sessions or trading liquidity.
• Changes in the ownership structure if pledged shares continue to be liquidated.