The Stock Exchange of Thailand (SET) has issued new oversight and disclosure rules, effective July 1, 2026, overhauling the previous requirements. The reforms apply to listed companies, REITs, and property and infrastructure funds, and aim to enhance transparency, align with international standards, and ensure timely investor information.

The key changes and practical implications are highlighted below.

Major Shareholder Reporting

When a shareholding change reaching or crossing 5% or any subsequent multiple of 5% is reported under section 246 of the Securities and Exchange Act or a tender offer is completed (except for voluntary delisting), listed companies must disclose an updated shareholder list for the month in which the triggering event occurred. The list must be compiled within five business days after month-end and disclosed within 14 days thereafter. Noncompliance will trigger a “notice pending” (NP) sign.

This replaces the previous requirement to disclose shareholder lists only at annual general meetings or on record dates. Companies should coordinate with their share registrars to meet the new event-driven timelines.

New Financial and Internal Control Disclosures

The new rules require disclosure of material impairment, expected credit losses, and unreturned business deposits when these reach specified thresholds. Companies must also disclose events or indicators that may materially affect their internal control systems.

Boards and audit committees should expect to escalate accounting and internal-control issues earlier, as these matters may now trigger standalone SET disclosure obligations—not just financial statement treatment.

Backdoor Listing

With the Securities and Exchange Commission’s regulation on material transactions (MTs) taking effect on July 1, 2026, and now serving as the primary, standalone framework governing acquisitions and disposals, the SET needed to issue a standalone rule on backdoor listing matters. These matters had been covered by a previous regulation on MTs issued by the SET.

The key differences between the SET’s new rule and the previous SET MT regulation on this issue are highlighted below:

• Broader asset scope: The new rule applies to any asset or business brought into a listed company, regardless of the seller’s identity, and is no longer limited to assets of unlisted companies.
• Director and management change trigger: If the asset acquisition also results in a change of more than half of the directors and executives of the listed company (a change from the previous trigger, which applied only to voting rights or power to control the appointment of directors), the SET may exercise its discretion to determine changes in the 12-month period before or after the acquisition.
• Substance built in: The substance-over-form concept is now embedded more directly into the rule, allowing the SET to review transactions that appear structured to avoid the backdoor listing requirements, including transactions that fall below the size of the 100% threshold but are still significant or may result in a material change of the controlling person.

Stricter Mandatory Delisting Criteria

The SET has also tightened the grounds for mandatory delisting to promote transparency and investor protection, most notably in relation to cash company oversight and free-float requirements.

Status-based cash company test

The cash company (analogous to a “cash shell” in other markets) review has shifted from a transaction-based trigger to a status-based assessment of whether a company still has active operations or holds predominantly passive assets regardless of any specific disposal.

Free-float rules

Previously, large-cap companies (paid-up capital ≥ THB 10 billion) could request a one-year grace period from IPO to meet the free-float requirement (15% of paid-up capital held by at least 150 shareholders). This waiver has now been abolished.

The SET has also tightened the timing for remedial action when a free float falls short of the thresholds. Previously, the remediation period generally started when the company reported that its free float was insufficient. Under the new rules, if a company later corrects its free float report to show that the free float was in fact insufficient, the period will be counted from when the issue should have been identified, not from the correction date. This may shorten the time available before a “noncompliance” (NC) sign applies.

Companies with a free float NC sign are required to submit a remedy plan within a specified period. Failure to cure may ultimately lead to delisting.