Mergers and acquisitions (M&A) are ultimately about creating value. Buyers and sellers consider valuation, financing, potential synergies, and the business’ future prospects. Yet, one factor that can materially affect these expectations is sometimes considered too narrowly: tax.
Tax runs throughout the M&A lifecycle, influencing how an acquisition is structured and financed, the risks and tax positions that may be carried over by a buyer, the ability to integrate the acquired business, and ultimately the value realised from the investment. The impact of decisions made at one stage may not be fully apparent until much later, says Pharatorn Vichiennet, Partner Tax & Legal – Business Tax, Deloitte Thailand.
The issue extends beyond compliance with tax rules at closing. Effective tax planning requires consideration of the entire ownership lifecycle.
This perspective is increasingly relevant as the international tax environment grows more complex. Deloitte’s 2026 Global Tax Policy Survey, based on 1,010 tax and finance leaders across 28 jurisdictions, identifies rising compliance requirements and complexity as major business concerns. When considering investment jurisdictions, 60% of respondents rated tax stability and certainty as the most important deciding factor, compared with 52% for the overall tax burden.
The findings reinforce an important point: tax planning is not simply about pursuing the lowest immediate tax cost. Predictability and certainty can also matter in investment decisions. For companies considering M&A, this perspective is relevant across three critical stages.
Before the acquisition: Look beyond the entry point
When structuring an acquisition, Mr. Pharatorn said the immediate focus often centres on how the business or shares will be acquired and the associated tax costs at closing. However, a structure that appears efficient at entry may not remain optimal throughout the investment lifecycle.
Acquisition financing, future funding needs, profit repatriation, subsequent integration and eventual exit may all be influenced by decisions made at the outset. These considerations are consistent with the initial Business Tax direction for the article.
A useful question is therefore not only, “what is the most tax-efficient way to make this acquisition?” but also, “will this structure provide sufficient flexibility for how we intend to own, operate and ultimately realise value from the business?”
Addressing these questions early can help preserve flexibility. Although post-acquisition restructuring may be possible, changing the structure later can introduce additional tax costs or other constraints. Considering the anticipated operating model, integration and exit at the outset can therefore help preserve the options available after closing.
During the acquisition: Understand what is behind the numbers
Tax due diligence is another area where looking beyond the immediate transaction can make an important difference.
A target may have reported tax losses, deferred tax assets or historical tax positions that appear straightforward in its financial information. Understanding their value, however, may require examining underlying records, assessing uncertain tax treatments and determining whether tax losses or other tax attributes can be utilised under the proposed ownership structure. These issues were specifically identified in the initial Business Tax direction.
The changing international tax landscape adds another dimension. Under Pillar Two, for example, the target’s historical tax position may not necessarily represent its future position under new ownership. Deloitte’s Global Tax Policy 2026 Survey found that 88% of respondents expect Pillar Two to result in higher overall tax.
Tax due diligence should therefore be more than an exercise in identifying historical tax exposures. The commercial question is what those findings mean for the transaction.
An identified tax risk may need to be reflected in valuation, pricing or contractual protections, rather than simply documented in a due diligence report. Identifying such issues early gives buyers and sellers an opportunity to assess their implications while options remain to address them.
After the acquisition: Make sure expected synergies can be realised
Closing a transaction marks the start of ownership, not the end of tax considerations.
Many transactions are underpinned by an investment case that assumes synergies from combining businesses, simplifying legal structures, or changing how capital and operations are organised. Realising those synergies may involve asset transfers, entity mergers, new financing arrangements or changes to intercompany arrangements.
If deal planning does not consider the related tax implications, post-completion economics may differ from what was originally expected.
Planning for post-acquisition tax considerations should therefore ideally begin before the transaction closes. The relevant question is not only, “what will we buy?” but also, “what will we need to do with the business after we buy it?”
Considering this question during deal planning allows you to assess potential tax consequences alongside anticipated integration benefits. It can also help management distinguish between synergies that appear attractive on paper and those that can be implemented efficiently in practice.
Looking beyond the transaction
Taken together, these stages point to a broader principle: tax planning in M&A should follow the investment, rather than stop at the transaction.
Doing so requires more than understanding the tax rules applying at the point of acquisition. Businesses can benefit from considering how tax interacts with the deal’s commercial objectives, including financing, transaction economics, the future operating model, integration plans, cross-border considerations and eventual exit.
A broader perspective can also help reveal consequences that management may not initially have anticipated. Experience across transactions and an understanding of evolving tax requirements can help businesses identify relevant questions early, when there may still be choices available to address them.
Ultimately, the value of effective M&A tax planning should not be assessed only by the tax cost visible when a transaction closes. It can also come from identifying issues early, preserving flexibility, avoiding unnecessary costs and protecting the value that the transaction was intended to create.
For buyers and sellers alike, looking beyond the transaction means considering not only how to complete today’s deal, but how its tax consequences may affect the business and its value tomorrow.
