Thailand’s merger control regime is principally governed by the Trade Competition Act, B.E. 2560 (2017) (the “Trade Competition Act”) and subordinate notifications issued by the Trade Competition Commission of Thailand (the “TCCT”). The TCCT is the principal enforcement authority, supported by the Office of the Trade Competition Commission. Businesses whose competition matters are specifically regulated under sectoral legislation, including certain telecommunications and energy businesses, fall outside the general merger control regime under the Trade Competition Act and are subject to the relevant sector-specific regime.

Thailand has a mandatory two-track filing regime. A merger that may result in a monopoly or a business operator having a dominant position in a market requires pre-merger approval and cannot be completed before TCCT clearance. A merger that may result in a significant reduction in competition, but does not result in a monopoly or dominant position, is subject to post-merger notification where the turnover of any one of the relevant business operators, or their aggregate turnover, in any relevant market is at least THB 1 billion (approximately USD 30.3 million / EUR 26.7 million). Post-merger notification must be made within seven calendar days of completion. The statutory review period for a pre-merger application is 90 calendar days, extendable by up to 15 calendar days (see Questions 16 and 19–21).

Foreign-to-foreign share or asset acquisitions are generally treated in TCCT practice as falling within the Thai merger control regime only where both the buyer and the target have a business presence in Thailand, whether directly or through entities within their respective single economic entities (each, an “SEE”). Once such nexus exists, turnover generated from sales to customers in Thailand may be relevant even where those sales originate from a relevant entity outside Thailand (see Questions 6, 7 and 11). A transaction involving a business operator that is already dominant in a relevant Thai market may also require pre-merger approval even in the absence of a horizontal overlap.

In considering a pre-merger application, the TCCT looks beyond competition effects to factors including business necessity, benefits to business promotion, serious harm to the economy and important consumer interests (see Questions 13–14). Intra-group restructurings between business operators forming part of the same SEE are exempt from the merger control requirements.

Thailand operates two merger filing tracks: (i) a pre-merger approval application and (ii) a post-merger notification. Each is mandatory where the statutory conditions applicable to the relevant filing track are met.

The parties must therefore self-assess whether a transaction falls within the Thai merger control regime and, if so, which filing track applies.

For transactions subject to pre-merger approval, completion is prohibited until approval has been obtained from the TCCT. There is no specific exemption for public bids under the Thai merger control regime. Accordingly, a public bid that requires pre-merger approval cannot be completed until approval has been obtained.

Thai law does not provide a formal procedure for a carve-out, hold-separate arrangement or trustee structure. A transaction may be structured so that the relevant Thai business, or any other part of the business giving rise to the Thai filing requirement, is not transferred to, or placed under the control of, the buyer until clearance has been obtained. However, this is not a statutory exception to the standstill requirement and would need to be assessed carefully on the facts of the particular transaction. There is no formal procedure for obtaining advance approval of such an arrangement from the TCCT. Nor is there any statutory derogation from the standstill requirement.

Transactions requiring only post-merger notification are not subject to a standstill requirement and may be completed before notification is made. The notification must subsequently be submitted within seven calendar days of completion.

A transaction must first fall within the statutory definition of a ‘merger’. This covers: (i) a business combination resulting in one business continuing while the other ceases to exist, or in the establishment of a new business; (ii) an acquisition of assets representing more than 50% of the total value of the assets used in the ordinary course of business of another business operator, based on its financial statements for the preceding financial year; and (iii) a direct or indirect acquisition of shares resulting in the buyer holding 25% or more of the voting rights in a public company under Thai securities and exchange law, or more than 50% of the voting rights in any other business operator.  A qualifying merger is subject to filing only if the applicable jurisdictional thresholds are met (see Question 6).

A merger undertaken for the purpose of an internal restructuring between business operators forming part of the same SEE is exempt from the merger filing requirements. An SEE exists where two or more business operators are under the common control. For this purpose, a business operator is regarded as having control over another business operator where it: (i) holds more than 50% of the voting rights in that business operator; (ii) has direct or indirect control over a majority of the votes at its shareholders’ meeting; or (iii) has direct or indirect control over the appointment or removal of at least half of its directors. Control may also be traced through successive levels of ownership, provided that the holding at each level satisfies the shareholding or shareholder-voting control tests in (i) or (ii).

An acquisition of a minority interest may constitute a merger where the target is a public company under Thai securities and exchange law and the acquisition results in the buyer holding 25% or more of the total voting rights. Accordingly, an acquisition may be caught even though it does not confer majority control. For other business operators, the threshold is more than 50% of the total voting rights, so a minority interest will not ordinarily be caught. A filing is required only if the applicable jurisdictional thresholds are also met (see Question 6).

Thai merger control does not apply an EU-style qualitative test of ‘decisive influence’ to determine whether a share acquisition constitutes a merger. Accordingly, veto rights over strategic matters, de facto influence arising from shareholder attendance or voting patterns, or other forms of influence do not, of themselves, cause a share acquisition below the applicable statutory voting-right threshold to constitute a merger. However, the separate control tests used to determine the scope of an SEE, and the prescribed aggregation rules must still be considered (see Question 4).

Thailand applies two sets of jurisdictional thresholds, depending on whether a transaction is subject to pre-merger approval or post-merger notification.

For pre-merger approval, a filing is required where a merger may result in a monopoly or a business operator having a dominant position. A monopoly exists where there is only one business operator in a relevant market, which can determine the price and quantity of its goods or services independently and has sales of at least THB 1 billion (approximately USD 30.3 million / EUR 26.7 million). A business operator is considered dominant where, in the preceding year: (i) it had a market share of at least 50% and sales of at least THB 1 billion (approximately USD 30.3 million / EUR 26.7 million) in a relevant market; or (ii) it was one of the three largest business operators in a relevant market and their combined market share was at least 75%. Under item (ii), an individual operator with sales below THB 1 billion or a market share below 20% is excluded. Market shares and sales of business operators forming part of the same SEE and operating in the same relevant market are aggregated.

For post-merger notification, the threshold is met where the merger does not result in a monopoly or dominant position but the sales of any one of the merging business operators, or their combined sales, in a relevant market in the preceding year are at least THB 1 billion.

For a share acquisition, the assessment generally focuses on the buyer and the target, and their respective SEEs. The seller is not treated as a separate merging party merely because it disposes of the shares. Sales and market shares of entities forming part of each merging party’s SEE are, however, aggregated for the purposes of applying the thresholds.

The thresholds are calculated by reference to sales in the relevant market rather than the parties’ total worldwide or company-wide revenues.

The thresholds may be satisfied by one party alone, and it does not matter which merging party satisfies them. A horizontal overlap between the parties’ activities is not required (see Question 1).

The jurisdictional thresholds are domestic rather than global in scope and are assessed by reference to sales and market shares in the relevant product or service market in Thailand. Sales made to customers in Thailand may be relevant even if the relevant products or services are supplied from outside Thailand.

Another key element is the ‘domestic presence’ test. In TCCT practice, a local presence is generally required on both sides of the transaction. Both the buyer group and the target group must have a corporate presence in Thailand, whether directly or through an entity within their respective SEEs (see Question 4). A foreign business operator with no establishment in Thailand generally does not fall within the merger filing regime merely because it makes sales to customers in Thailand.

The thresholds are not subject to an automatic periodic adjustment mechanism but may be amended by the TCCT through subordinate legislation. The Trade Competition Act requires the TCCT to review the market-share and sales thresholds for dominance at least once every three years. On 22 September 2026, the TCCT opened a public consultation on draft notifications proposing, among other matters, to reduce the sales thresholds for monopoly, dominance and post-merger notification from THB 1 billion to THB 500 million (approximately USD 15.1 million / EUR 13.4 million), and to lower the single-firm dominance market-share threshold from 50% to 33%. These proposed changes are not yet in force (see Question 36).

The relevant thresholds are fixed amounts or percentages and are not determined by reference to any external factor.

For turnover and market-share purposes, the assessment is made by reference to the relevant product or service market in Thailand. For the dominance test, both turnover and market shares are assessed by reference to the preceding year, and the sales and market shares of business operators forming part of the same SEE and operating in the same relevant market are aggregated. The post-merger notification threshold is likewise assessed by reference to sales in the preceding year.

Sales attributable to a relevant market in Thailand are taken into account. Accordingly, sales to customers in Thailand may be relevant even where the relevant products or services are supplied from outside Thailand. Conversely, sales to customers outside Thailand would not ordinarily form part of sales in a relevant geographic market limited to Thailand.

Market share may be calculated by reference to sales volume, sales value, production volume or production capacity, as appropriate to the relevant market. The relevant market comprises both a product or service market and a geographic market. The geographic market is not necessarily national and depends on the area in which the relevant products or services are sold or provided under similar conditions of competition. In practice, the relevant geographic market is often national, although a narrower geographic market may be appropriate depending on the characteristics of the relevant product or service.

Where the TCCT has not previously considered the relevant market, the parties must make their own good-faith assessment of the appropriate market definition and their market shares. There is no statutory requirement to obtain prior confirmation of that assessment from the TCCT.

Asset value is relevant to determining whether an asset acquisition constitutes a ‘merger’, it is not  a separate jurisdictional filing threshold. The merger control rules do not prescribe a separate geographic allocation test for asset values. An acquisition constitutes a merger under the asset-acquisition limb where the assets acquired represent more than 50% of the total value of the assets used in the ordinary course of business of another business operator, based on its financial statements for the preceding financial year

The value of the assets being acquired is determined by reference to their book value as at the date of the relevant agreement or acquisition, as applicable.

Where figures are denominated in a foreign currency, the prescribed merger filing form requires them to be converted into Thai baht using the average selling rate published by the Bank of Thailand (BOT). The filing should identify the foreign currency, the exchange rate used and the relevant date, with supporting evidence of the BOT rate.

For reference, the BOT annual average selling rates for 2025 were approximately THB 33.05 per USD 1 and THB 37.43 per EUR 1. These rates are used throughout this chapter to convert THB figures into USD or EUR.

Thai merger control does not contain a separate filing requirement or separate jurisdictional thresholds for joint ventures. Instead, the transaction steps used to establish, acquire or restructure a joint venture must be assessed under the ordinary merger control rules (see Questions 4–7).

The creation of a new ‘greenfield’ joint venture with no pre-existing business does not, by itself, constitute a notifiable merger. However, where a new joint venture is established through an amalgamation or through a transfer or acquisition of shares or assets involving an existing business operator, those underlying transaction steps may constitute a merger and be subject to the applicable filing requirements. Thailand does not apply a separate ‘full-function’ or autonomy test to determine whether a joint venture falls within the merger control regime. Joint venture arrangements must also be assessed separately under the prohibitions on anticompetitive agreements, where applicable, even if no merger filing is required.

The entities and groups relevant to the jurisdictional assessment therefore depend on the particular transaction step constituting the merger. For example, an acquisition of shares in an existing joint venture is assessed by reference to the buyer, the target joint venture and their respective SEEs, whereas an acquisition of assets by or for a joint venture is assessed under the ordinary asset-acquisition rules.

The SEE exemption may also be relevant (see Question 4). A merger undertaken for the purpose of an internal restructuring between business operators forming part of the same SEE is exempt from the merger filing requirements. Accordingly, where a parent and a joint venture form part of the same SEE, a qualifying transaction between them may fall within this exemption. The exemption would not generally apply merely because a parent holds an interest in a joint venture where the relevant entities do not form part of the same SEE.

Thai merger control does not contain specific rules determining whether different stages of the same overall transaction must be treated as a single merger or as separate transactions.

In practice, where multiple transaction steps are interdependent and form part of a single overall transaction, the TCCT may accept a single merger filing covering those steps. Conversely, where linked transaction steps are independent of one another and each independently constitutes a ‘merger’ in its own right and meets the applicable jurisdictional thresholds, separate filings may be required. Accordingly, multi-stage transactions, including successive share or asset acquisitions or transactions involving multiple buyers, should be assessed by reference to the particular transaction structure and the interdependence of the relevant steps.

Where separate pre-merger approval applications are required, the filing fee of THB 250,000 (approximately USD 7,600 / EUR 6,700) is payable for each application. No filing fee is prescribed for post-merger notifications.

The jurisdictional thresholds do not differ merely because a transaction is ‘foreign-to-foreign’. The ordinary merger tests and filing thresholds apply in the same manner to domestic and foreign-to-foreign transactions (see Questions 4–7).

However, the domestic presence test remains relevant (see Question 6). In TCCT practice, both the buyer and the target must have the requisite business presence in Thailand, whether directly or through an entity within their respective SEEs. Accordingly, a foreign-to-foreign transaction may be subject to Thai merger control where both sides have such Thai presence, even though the entities directly involved in the acquisition are incorporated outside Thailand. Conversely, where either side lacks the requisite Thai presence, the transaction would generally fall outside the Thai merger control regime.

The Thai regime therefore does not generally create a technical filing requirement for a transaction with no Thai nexus merely because the parties satisfy the relevant turnover thresholds.

Not applicable.

The Trade Competition Act does not prescribe a single substantive test equivalent to the EU ‘significant impediment to effective competition’ or US ‘substantial lessening of competition’ test for pre-merger approval. In practice, the TCCT considers market definition and structure before and after the merger, market shares and concentration, barriers to entry and expansion, non-coordinated and coordinated effects, market efficiency and effects on consumers and the wider economy. These factors may capture horizontal, vertical and conglomerate competition concerns, depending on the transaction. The TCCT’s analysis has tended to place greater emphasis on market structure than on an effects-based lessening-of-competition analysis, which differs from the approach commonly taken in the EU and US.

In determining whether to approve the merger, the TCCT must also consider the statutory factors of reasonable business necessity, benefits to business promotion, whether the transaction would cause serious harm to the economy and whether it would adversely affect important consumer interests. Approval may be granted subject to conditions.

There is no separate substantive test under the general regime for particular sectors. However, businesses in sectors subject to specific competition legislation, such as telecommunications and energy, may instead fall under the relevant sector-specific substantive test.

Yes. As noted in Question 13, in addition to competition-related considerations, the TCCT must take into account certain broader statutory factors when assessing a pre-merger application, including reasonable business necessity, benefits to business promotion, whether the transaction would cause serious harm to the economy and whether it would adversely affect important consumer interests.

No. Ancillary restraints are not expressly reviewed or cleared by the TCCT as part of a merger clearance decision. The TCCT has not issued guidance or established a safe harbour for ancillary restraints agreed in connection with a transaction. Accordingly, the parties must separately assess whether such restraints comply with the Trade Competition Act and other applicable Thai law.

There is no prescribed maximum permissible duration for a non-compete covenant imposed on a seller. Its enforceability and compliance with Thai competition law therefore depend on the particular circumstances, including its duration, geographic scope and the business activities it restricts. The TCCT has not published specific parameters for seller non-compete covenants in the M&A context.

For pre-merger approval, there is no statutory deadline by which the application must be submitted. However, clearance must be obtained before completion of the transaction. Once the TCCT receives a complete pre-merger application, it has 90 calendar days to complete its review, which may be extended by up to 15 calendar days if necessary.

Parties should also allow sufficient time before formal submission to prepare the application and supporting documents. In practice, parties may engage in informal pre-filing consultation with TCCT officers to confirm the completeness of the filing, although such consultation is not mandatory and is not subject to a statutory timetable. A preliminary letter or informal notification would not satisfy the formal filing requirement.

For post-merger notification, the prescribed notification form and supporting documents must be submitted within seven calendar days from the date of completion of the merger. A letter merely informing the TCCT of the transaction does not satisfy this requirement.

For a pre-merger approval application, there is no statutory triggering event or prescribed earliest filing date.

In practice, pre-merger applications are generally submitted once the parties have entered into a definitive agreement. The parties may begin informal pre-filing consultation with TCCT officers before signing the definitive agreement, although the signed agreement will need to be submitted with the formal application.

A post-merger notification can only be submitted after completion of the transaction, as the date of completion triggers the seven-calendar-day notification period.

Yes. Although pre-notification discussions with the TCCT are not mandatory or prescribed by law, informal consultations are commonly undertaken and are generally recommended in practice before a formal pre-merger filing.

There is no prescribed timetable for this process. The duration depends on the complexity of the transaction, the completeness of the information and supporting documents, and the availability of TCCT officers. As a practical matter, parties are generally advised to engage with the TCCT approximately one month before submitting a pre-merger approval application. More complex transactions or those raising potential competition concerns may require a longer period of consultation.

For a pre-merger approval application, the statutory review period begins once the TCCT has received the complete application and formally accepted it. The TCCT must complete its review within 90 calendar days, extendable by up to 15 calendar days where necessary. During the review, the TCCT may request additional information from the parties or seek information or views from third parties.

For post-merger notifications, there is no prescribed statutory review period. In our experience, the TCCT has generally taken approximately two to nine months from submission to issue its final acknowledgement.

For a pre-merger approval application, the statutory review period does not begin until the application and required supporting documents are complete and formally accepted by the TCCT. If the filing is incomplete, the TCCT may require the applicant to correct the deficiencies or provide additional documents.

Once the application has been formally accepted, the TCCT must complete its review within 90 calendar days. Where necessary, this period may be extended once by up to 15 calendar days. Thai merger control rules do not provide for a separate ‘stop-the-clock’ or reset mechanism during this statutory review period. Accordingly, requests for further information, discussions of remedies, further clarification of information already submitted or the involvement of third parties do not automatically suspend or restart the review period.

For post-merger notifications, there is no statutory review timetable and therefore no corresponding statutory mechanism for extending, resetting or suspending any review period.

There is no formal expedited or shortened review procedure under the Thai merger control regime. The 90-calendar-day review period is a maximum period, so the TCCT may issue its decision at any time before the period ends, once its review is complete. In practice, early pre-filing consultation and submission of a complete application may help avoid delays, but parties should not expect to obtain clearance before the expiry of the statutory review period and should take into account the possible 15-calendar-day extension when planning the transaction timetable.

For post-merger notifications, there is no statutory review timetable and therefore no formal procedure for shortening it.

For pre-merger approval, the filing obligation rests with the business operators that are to merge. In a share acquisition, this generally means the buyer and the target; in an asset acquisition, it means the buyer and the seller of the assets. For a post-merger notification, the obligation rests with the business operator carrying out the merger, which in an acquisition is generally the buyer. These are also the parties that may be subject to penalties for failure to comply with the applicable filing obligation. In practice, the target or seller will often be required to cooperate in providing information and documents needed for the filing.

Thai merger control does not treat an acquisition of joint control or the creation of a new joint venture as a separate filing category. The underlying share, asset or business acquisition must instead be assessed under the ordinary merger rules. Where there are multiple buyers, the filing obligation rests with the party or parties carrying out the qualifying acquisition.

For a pre-merger approval application, the filing requires detailed information on the parties and their group structures, the transaction, corporate and financial details, shareholding and control, relevant products and services, market definition, turnover and market shares, competitors, customers and suppliers, and the expected competitive effects of the transaction. The TCCT may request additional information or explanations during its review where it considers this necessary.

For a post-merger notification, the information requirements are generally less extensive. The filing typically covers the parties, group structures, transaction details, pre- and post-merger shareholdings, Thai turnover, relevant markets and market shares. The TCCT may also request further information after submission.

There is no short-form or simplified filing procedure under the Thai merger control regime.

The supporting documents depend on the nature of the transaction and whether the filing is made under the pre-merger or post-merger regime. They generally include:

• corporate documents, including certificates of incorporation or corporate affidavits, articles of association and shareholder lists, as applicable, from each merging party;
• transaction documents, including definitive agreements, the merger plan and timetable, and board or shareholder resolutions approving the transaction or other evidence of the parties’ intention to proceed;
• financial records, including annual reports and audited financial statements of the relevant parties for the preceding three years;
• market information, including materials supporting the market definition, market-share and competitive-effects analysis; and
• power of attorney, where the filing is signed or submitted through an authorised representative.

Supporting documents must be in Thai or accompanied by a certified Thai translation. The prescribed filing rules do not impose a general notarisation or apostille requirement, although copies must generally be certified by an authorised signatory or authorised representative, with the company seal where applicable. There is no prescribed requirement as to how recent the documents must be. However, they should reflect the parties’ current and valid information.

For a pre-merger application, the filing form is signed on behalf of both the acquiring and target sides by their authorised signatories or duly authorised representatives. For a post-merger notification, the form is signed by the business operator responsible for the notification or its authorised representative.

Yes. A filing fee of THB 250,000 (approximately USD 7,600 / EUR 6,700) is payable for each pre-merger approval application. No filing fee is prescribed for a post-merger notification.

No public announcement is made when a merger filing is submitted.

Once the filing is complete, the TCCT issues an acknowledgement of receipt to the notifying party, but this is not published. The TCCT publishes summaries of rulings concerning pre-merger approval applications and post-merger notifications on its official website (www.tcct.or.th). The names and identifying details of the parties are generally redacted.

The TCCT has the power to invite any person to provide facts, explanations, advice or opinions for its consideration. However, there is no mandatory third-party consultation or formal market-testing process under the Thai merger control regime. Accordingly, there is no specific exemption from third-party consultation for transactions that clearly raise no competition concerns.

The law does not prescribe which categories of third parties must be consulted or require consultation in every case.

Where the TCCT does seek third-party views, it does so at its discretion during the review period.

The parties’ notification, supporting documents and other submissions made during the review process are not generally published or made available to third parties. Instead, the information made public is principally contained in the TCCT’s published ruling, which presents the TCCT’s own summary and analysis of the transaction rather than reproducing documents submitted by, or issued directly to, the parties.

Published rulings generally set out the relevant markets, the TCCT’s competitive assessment and its conclusions on the effects of the merger, including whether the transaction creates or strengthens a dominant position or significantly reduces competition. Commercially sensitive information is typically redacted, including exact sales figures,  precise market shares and, in many cases, the identities of the parties.

Where the TCCT publishes a ruling, the public version is separate from the decision letter issued to the parties, which is not generally published. Publication takes place on a rolling basis throughout the year, depending on when merger filings are submitted and when the TCCT completes its review, rather than according to any fixed publication timetable. In practice, the TCCT decides what information to include in the published rulings, and the parties are not generally given a separate opportunity to review or approve the published version in advance. Parties should therefore identify confidential information and explain the grounds for confidential treatment when submitting it.

The TCCT cooperates with foreign competition authorities and has entered into memoranda of understanding with authorities including the Philippine Competition Commission and the Australian Competition and Consumer Commission, covering matters including information exchange, enforcement cooperation and technical assistance.

The Office of the Trade Competition Commission is also empowered under the Trade Competition Act to exchange information and cooperate with agencies outside Thailand. The Trade Competition Act does not provide for any specific sanction where a party declines to authorise the disclosure of its confidential information to another authority, including a foreign competition authority. It generally restricts disclosure of non-public business information obtained in the course of performing functions under the Trade Competition Act, subject to limited exceptions. We are not aware of any published ruling clarifying whether those exceptions would permit disclosure to a foreign competition authority to assist with an investigation.

The TCCT may approve a transaction subject to conditions. In the published decisions we have reviewed, the TCCT has generally relied on behavioural remedies, including obligations relating to commercial arrangements, non-discrimination, continued access to products or services, information barriers, compliance and reporting. Behavioural remedies have therefore been prominent in Thai practice, although the limited number of published decisions makes a direct comparison with EU or US practice difficult.

By contrast, we are not aware of any published TCCT merger decision requiring a structural divestment remedy, and there are no published divestment guidelines. There is therefore no established practice on up-front buyers or purchaser-approval criteria; these would need to be assessed case by case.

There is no separate statutory remedies procedure or prescribed deadline for offering remedies. The parties may propose remedies, and the TCCT may also attach conditions of its own when approving a transaction. Remedies may be discussed and accepted within the single statutory review period; there is no separate second phase. The Thai merger control rules do not require remedy proposals to be market tested, although the TCCT may seek third-party views under its general power to invite any person to provide information or opinions (see Question 27). There is no formal mechanism for the TCCT to waive a remedy because one has been agreed in another jurisdiction.

The consequences depend on whether the transaction is subject to pre-merger approval or post-merger notification.

• Failure to obtain pre-merger approval / closing before clearance: the business operators responsible for the merger may be subject to an administrative fine of up to 0.5% of the transaction value. The same maximum fine applies where a business operator fails to comply with the time period or conditions attached to an approval, in which case the TCCT may also revoke the approval in whole or in part. In addition, the TCCT may order the parties to suspend, cease or modify the relevant conduct. Non-compliance with such an order may attract a further administrative fine of up to THB 6 million (approximately USD 181,500 / EUR 160,300), plus up to THB 300,000 (approximately USD 9,100 / EUR 8,000) per day while the non-compliance continues.
• Failure to make, or delay in making, a post-merger notification: the responsible notifying party may be fined up to THB 200,000 (approximately USD 6,100 / EUR 5,300), plus up to THB 10,000 (approximately USD 300 / EUR 270) per day for the period of continuing non-compliance.
• Individual liability: where the infringing party is a juristic person, directors, managers or other responsible persons may also be subject to the same administrative penalty if the infringement results from their act, instruction or relevant omission. There are no criminal penalties specifically for failure to comply with the merger filing requirements.

The Trade Competition Act does not expressly provide that a transaction completed in breach of the merger filing requirements is void or invalid.

We are not aware of any case in which the TCCT has imposed a fine for failure to obtain pre-merger approval. The TCCT has, however, fined business operators (and, in some cases, their directors) for late post-merger notifications. We are not aware of any published penalty decision specifically concerning a foreign-to-foreign transaction, although the same rules apply where both sides have the requisite Thai presence (see Question 6). To minimise risk, parties should:

• assess the Thai filing position early, including the Thai presence of each party’s SEE;
• where pre-merger approval is required, make TCCT approval a condition precedent;
• ensure that neither the Thai business nor control over it passes to the buyer before clearance (see Question 3); and
• for post-merger notifications, prepare the filing and supporting documents before completion so that the seven-calendar-day deadline can be met and, if the deadline is missed, file as soon as possible to limit the daily fine.

The Trade Competition Act does not prescribe a separate merger-specific fine solely for submitting incomplete or misleading information. This does not exclude liability under other applicable laws. In particular, a person who knowingly gives false information to an official in circumstances that may cause damage to another person or the public may face imprisonment for up to six months, a fine of up to THB 10,000 (approximately USD 300 / EUR 270), or both, under the Criminal Code.

In addition, an incomplete pre-merger application will not be formally accepted until the deficiencies are corrected; if they are not remedied within the period specified by the TCCT, the application may be returned.

During the review, the TCCT may request further information or clarification. Failure to comply with a summons issued by TCCT officers may result in imprisonment for up to three months, a fine of up to THB 5,000 (approximately USD 150 / EUR 130), or both.

For both pre-merger applications and post-merger notifications, the filing party must certify that the information and supporting documents are complete, accurate and not false, and the TCCT may request further clarification or information after filing.

Yes. A business operator that receives an order granting or refusing pre-merger approval and disagrees with that order may bring an action before the Administrative Court within 60 calendar days from the date on which it is notified of the decision. Third parties may also seek judicial review under the general administrative court rules if they can establish the required grievance or injury and satisfy the other standing requirements. The general filing period is 90 calendar days from the date on which the cause of action became known or should have become known, subject to any applicable special rule or exception. The 60-calendar-day period for the recipient of a pre-merger order should therefore not be treated as a deadline for every challenge.

There is no statutory deadline for the Administrative Court to complete its review. In practice, proceedings can be lengthy and may take several years before a final judgment is delivered.

The TCCT’s merger control practice continues to develop. TCCT officers commonly scrutinise the information on turnover, market shares, market definition, competitors, customers and suppliers before formally accepting a pre-merger application. For more complex or high-profile transactions, this process can materially extend the overall timetable.

Where competition concerns arise, the TCCT’s published decisions have generally favoured behavioural conditions, including non-discrimination, access obligations, information-sharing restrictions, restrictions on further acquisitions and reporting obligations. We are not aware of any published TCCT merger decision imposing a structural divestment remedy or prohibiting a transaction outright. The relatively limited body of published decisions means that the TCCT’s approach, particularly to complex transactions and structural remedies, is still evolving.

Yes. On 22 September 2026, the TCCT opened a public consultation, scheduled to close on 21 October 2026, on draft amendments to three pieces of subordinate legislation under the Trade Competition Act, including the rules governing pre-merger approval and post-merger notification. The proposals are still at an early stage and may change following the consultation. Under the current drafts, the amendments would, among other things, revise the criteria for dominance (including lowering the single-firm market-share threshold from 50% to 33% and replacing the current three-firm test with a two-firm test), reduce the sales thresholds for dominance, monopoly and post-merger notification purposes from THB 1 billion to THB 500 million (approximately USD 15.1 million / EUR 13.4 million), and introduce alternative criteria for assessing dominance in fast-moving and platform-based markets, such as digital markets. The launch of the public consultation does not, however, indicate when the proposed amendments will be finalised or come into force.