ArticleTaxM&A

Deal Costs in M&A: Deductible Expense or Acquisition Cost?

25 Aug 2026

Transaction costs can be a significant cost item in an M&A process. Whether they are immediately deductible or increase the acquisition cost depends on what caused the expense.

Legal fees, tax advice, financial due diligence, commercial due diligence and other transaction costs can quickly become a significant cost item in an M&A process For an overview of M&A advisory costs, see our separate article.

A common assumption is that these costs can simply be deducted as operating expenses by the acquisition vehicle.

That is not necessarily the case.

For an acquisition GmbH acquiring shares in a target company, the tax treatment of transaction costs depends primarily on what the respective costs relate to and how closely they are connected to the specific acquisition.

M&A deal costs and tax: the short answer

Transaction costs of a business acquisition are not automatically deductible straight away. Costs that are economically attributable to the acquisition of a specific participation may qualify as incidental acquisition costs (Anschaffungsnebenkosten) and increase the acquisition cost of the participation.

Other costs may be treated differently where they cannot be sufficiently attributed to the specific acquisition. What matters is the individual service, its economic cause and the stage of the transaction.

The invoice title or the invoice date alone does not determine the tax treatment.

Typical deal costs and what needs to be reviewed

Cost typeKey tax question
Legal due diligenceConnection with the specific acquisition
Tax due diligencePurpose and allocation of the individual service
Financial due diligenceConnection with the acquisition review and the acquisition
SPA adviceUsually close connection with the specific transaction
Tax structuringSpecific service and its cause
Acquisition financingSeparate tax classification required
General corporate adviceDistinction from the specific acquisition work

The table is not a general tax classification of individual cost types. Different services within the same workstream may also be treated differently.

The key question: What caused the expense?

The timing of an invoice is not decisive on its own.

Instead, the relevant question is whether the expenditure is economically attributable to the acquisition of the shares.

Where transaction costs are directly attributable to the acquisition, they may qualify as incidental acquisition costs (Anschaffungsnebenkosten) of the participation.

This can apply, for example, to certain legal, tax, due diligence or other advisory costs incurred specifically for the acquisition of the target.

In that case, the costs are not immediately deductible as operating expenses. Instead, they increase the acquisition cost of the participation.

Other expenses may be treated differently where they are not sufficiently attributable to the actual acquisition.

The classification therefore requires an analysis of the individual services rather than simply treating every invoice connected with the transaction in the same way.

In practice, the label “M&A advisory”, “due diligence” or “tax advisory” is not decisive. What matters is which specific service was provided and what purpose it served.

One important dividing line: the acquisition decision

The acquisition decision can be an important timing and economic dividing line. It is not an automatic switch that makes all earlier costs immediately deductible and all later costs incidental acquisition costs.

A particularly relevant question is when the buyer moved from evaluating a potential opportunity to pursuing a specific acquisition.

Costs incurred at a stage where potential targets are still being screened and the acquisition decision remains genuinely open may have to be assessed differently from costs incurred once the buyer has made a fundamental decision to pursue the acquisition of a specific target.

This distinction can be particularly relevant for due diligence, tax structuring and other advisory work.

In practice, this means that the transaction timeline matters.

Relevant questions may include:

  • When was the target first identified?
  • When did the buyer decide in principle to pursue the specific acquisition?
  • When were advisors instructed?
  • What exactly were they instructed to analyse or negotiate?
  • Did the work still serve to identify or evaluate potential opportunities, or was it already directed at implementing a specific acquisition?

There is therefore not always a single moment at which every transaction cost suddenly receives the same tax treatment.

The underlying activity and its connection to the acquisition remain decisive.

The timeline helps with the analysis. The economic cause of each individual service remains decisive.

Are due diligence costs tax deductible?

A general answer is not useful. Due diligence work can be structured in different ways and incurred at different stages.

The key point is whether, and how closely, the specific review is connected with the acquisition of a particular target.

That is why the content of each workstream should be considered, not just the invoice as a whole.

What about legal and tax advice?

Legal and tax advice in a transaction can also cover several different services, for example:

  • general tax structuring considerations
  • tax due diligence
  • legal due diligence
  • corporate structuring
  • SPA negotiation
  • financing structure
  • management participation
  • general corporate housekeeping

These services do not necessarily receive the same tax treatment. The more precisely scope and invoice descriptions are documented, the easier the later allocation becomes.

Why this matters

For smaller transactions, the distinction may appear technical.

For larger transactions, it can have a material impact.

If an acquisition vehicle incurs EUR 50,000, EUR 100,000 or EUR 200,000 of advisory costs, the question whether those costs are immediately deductible or must be capitalised can materially affect the company's taxable result.

This is particularly relevant for acquisition vehicles, which often incur substantial transaction costs before generating meaningful operating income of their own.

A tax deduction that is assumed in the transaction model but ultimately turns out to require capitalisation can therefore materially change the expected tax position of the acquisition structure.

One invoice does not necessarily mean one tax treatment

The issue becomes even more practical where one advisor provides several types of services under the same engagement.

A single legal or tax invoice may, for example, cover work relating to:

  • the acquisition agreement
  • tax due diligence
  • acquisition financing
  • corporate structuring
  • management participation
  • general corporate matters

Those services do not necessarily have to receive the same tax treatment.

A meaningful breakdown of the underlying services can therefore become important.

Generic invoice descriptions such as “M&A advisory services” may make the subsequent allocation unnecessarily difficult.

For material transaction costs, the scope of work, engagement documentation and invoice descriptions should therefore allow the individual workstreams to be identified.

For larger transactions, the engagement terms and internal cost control should keep the different workstreams separately traceable.

Generic collective descriptions make the tax classification unnecessarily difficult.

Deal cost allocation should start before closing

The tax treatment of transaction costs should not be considered for the first time when the annual financial statements are prepared.

During the transaction, the buyer should already have a clear picture of:

  • which transaction costs are being incurred
  • which services the respective costs relate to
  • at what stage of the transaction they were incurred
  • how closely they relate to the acquisition of the specific target
  • how the costs should be documented and allocated for tax purposes

This is also relevant where a transaction ultimately does not close.

A failed deal does not automatically mean that every transaction cost can simply be treated as an immediately deductible expense. The underlying purpose and circumstances in which the respective costs were incurred still need to be analysed.

Deal cost tracking during the transaction

The tax classification becomes easier when deal costs are recorded in a structured way during the transaction.

Practical points:

  • adviser and workstream
  • service period
  • specific activity
  • stage of the transaction
  • connection with the specific target
  • invoice and service description
  • internal allocation where relevant

For an acquisition GmbH working with several advisers, ongoing deal cost tracking can prevent the entire analysis from having to be done after closing as part of the annual financial statements.

Why this matters for the acquisition GmbH

In many acquisitions, a newly formed acquisition vehicle bears a large part of the deal costs.

There, the question whether costs hit the result immediately or increase the acquisition cost of the participation can have a material effect on the company's tax position. The treatment should therefore already be reflected in the financing model and transaction planning.

Transaction structuring and tax treatment belong together

Deal costs are often discussed primarily as a budgeting issue:

How much will legal counsel, tax advisors, financial advisors and due diligence providers cost?

But there is a second question that should be addressed at the same time:

What happens to those costs for tax purposes?

For acquisition vehicles in particular, the answer can make a meaningful difference.

The practical takeaway is therefore simple:

Target screening, acquisition decision, transaction execution and closing should not be viewed as one undifferentiated cost block.

The tax treatment of deal costs should be considered alongside the transaction itself — and not only after closing.

How high the different deal costs can be and which advisers may be involved in an acquisition is covered in our article How Much Does M&A Advisory Cost When Buying a Business?. For support, see our Tax and Transactions practices.

FAQ

Are M&A deal costs tax deductible in Germany?

There is no general answer. What matters is which specific service the costs relate to and how closely they are economically connected with the acquisition of the participation.

Are due diligence costs operating expenses?

Due diligence costs cannot be classified for tax purposes based on their label alone. Content, purpose and connection of the specific review with the acquisition are relevant.

What are incidental acquisition costs in a business acquisition?

Incidental acquisition costs (Anschaffungsnebenkosten) are expenses attributed to the acquisition of an asset or participation that may increase the acquisition cost. Whether specific transaction costs fall into this category has to be reviewed for each service.

Does the invoice date decide the tax deduction?

No. The invoice date alone is not decisive. The economic cause of the underlying service is what matters.

What happens to deal costs if the transaction does not close?

Even for a failed deal, the tax treatment has to be reviewed based on the specific service and its economic cause. A failed deal does not automatically lead to uniform treatment of all costs.

Why should individual workstreams be documented separately?

Because legal, tax, financing and due diligence services within the same transaction can serve different purposes. Clear documentation makes the tax classification easier.

Think about deal structure and deal costs early.

We support buyers with tax due diligence, acquisition structure and the tax classification of transaction costs.