
The shift forces deal teams to embed tax risk assessment early, reshaping valuation, due‑diligence costs and transaction timelines across the M&A market.
The modern tax advisory landscape reflects a broader regulatory crackdown and heightened public scrutiny. As tax authorities coordinate internationally and courts reject opaque structures, the traditional allure of aggressive tax planning has faded. Dealmakers now treat tax advice as a risk‑management function, demanding clear evidence that historic positions will survive regulatory review and public disclosure. This paradigm shift compels corporations to prioritize certainty and defensibility, moving away from speculative savings toward stable, compliant structures.
In M&A due diligence, the focus has turned inward, examining the tax legacy a target brings to the table. Historic arrangements—often crafted under different legal regimes—can trigger valuation adjustments, trigger warranty claims, or necessitate indemnity provisions. Buyers increasingly request detailed documentation and scenario analyses to gauge potential exposure, while sellers must proactively address any red flags to avoid transaction delays or price erosion. The heightened emphasis on tax risk also inflates advisory spend, as firms enlist specialists to map legacy positions and model post‑transaction outcomes.
Looking ahead, the role of the tax lawyer is evolving from technical architect to strategic partner. Automation and AI handle routine calculations, but human judgement remains essential for interpreting grey‑area risks and advising on reputational implications. Advisors are now embedded in deal teams from the outset, shaping structures that balance fiscal efficiency with regulatory resilience. Simplifying the tax code would further reduce friction, yet until political will materialises, firms must rely on defensible, well‑documented tax strategies to safeguard transactions and stakeholder trust.

Before founding his own policy-focused organisation, Dan Neidle spent more than two decades at Clifford Chance, rising to become the firm’s senior London tax partner. During that time, he advised multinational corporates, financial sponsors and boards on some of the most complex tax questions embedded in major transactions.
Today, his perspective on tax advice reflects how dramatically the role of the tax lawyer has changed — particularly for dealmakers navigating acquisitions, exits and reputational exposure.
Finance Monthly spoke with Neidle about why tax advice is no longer about optimisation, how historic decisions now shape deal outcomes, and what sophisticated clients really want from their legal advisers.
Dan Neidle:
Not at the serious end of the market. Large corporates, institutional investors and private equity sponsors are not looking for clever tricks. They’re looking for certainty.
“Tax advice today is fundamentally about risk. Clients want to know what could go wrong, what might be challenged, and whether something done years ago could suddenly become a problem in the middle of a transaction.”
That’s a very different mindset from the past. The emphasis has shifted from optimisation to exposure management, particularly when deals are under scrutiny from regulators, investors and the public.
Neidle:
Tax advisers are increasingly focused on the past rather than the future. In acquisitions, the key question is often not how to structure the deal, but what the buyer is inheriting.
Historic tax positions — sometimes taken decades ago — can sit quietly until a sale, IPO or refinancing forces everything into the open. Some of those positions were taken in a very different legal and enforcement environment, and they don’t always stand up well today.
For buyers, that can affect valuation, warranties, indemnities, insurance, and occasionally whether the deal goes ahead at all.
Neidle:
It’s very real. Tax authorities are better resourced, better coordinated internationally and much more confident about litigating.
“The era when large companies could rely on complexity or opacity to manage tax exposure has gone. If something is aggressive, it will eventually be challenged — and in most cases, the taxpayer will lose.”
Courts are also far less tolerant of artificial arrangements. That reality feeds directly into how boards and deal teams think about risk.
Neidle:
In many cases, more than the legal risk itself.
Clients don’t just ask whether something is lawful. They ask how it would look if it were public, how it would read in a prospectus, or how it might be interpreted by a regulator or parliamentary committee years later.
Tax behaviour has become a proxy for governance. Advisers have to factor that in, because a technically defensible position can still be commercially disastrous if it undermines trust.
Neidle:
Very rarely — at least where serious capital is involved.
“The cost-benefit calculation no longer makes sense. You might save some tax, but you introduce uncertainty, delay transactions, and potentially invite scrutiny that far outweighs the upside.”
What clients increasingly want are boring, defensible positions. That may not sound exciting, but when you’re executing a complex deal or preparing for an exit, boring is exactly what you want.
Neidle:
Exits are where historic decisions really surface. When you prepare for a sale or IPO, everything is reviewed in detail — often far more closely than when those decisions were originally made.
Structures that were put in place early on, sometimes with limited documentation or poor advice, can suddenly become very visible. Even if they don’t derail a transaction, they can slow it down or reduce value.
Good advisers help clients identify and address those issues early, before buyers start asking uncomfortable questions.
Neidle:
Yes — particularly around strategy and judgement. There’s a tendency to assume that legal force automatically gives you control over a situation.
“Threatening litigation can be a spectacularly bad move, especially in matters that touch on public interest or governance. Instead of containing an issue, it can amplify it.”
Part of modern legal advice is telling clients when not to escalate. Just because something is legally possible doesn’t mean it’s strategically sensible.
Neidle:
Absolutely. Decades of anti-avoidance legislation have produced a very dense system that increases compliance costs without necessarily improving outcomes.
From a deal perspective, complexity slows transactions, increases advisory spend and creates uncertainty. Simplification would benefit business without materially reducing tax revenue — but it requires political will.
Neidle:
Technical expertise will always matter, but judgement matters more.
As automation and AI take over routine analysis, the value of advisers lies in assessing risk, anticipating scrutiny and guiding clients through grey areas with confidence. Tax lawyers are increasingly strategic advisers embedded in deal teams from the outset.
Neidle:
Defensibility and clarity. Understand your historic positions, document your reasoning and avoid anything that relies on optimism rather than evidence.
Deals are hard enough without carrying unnecessary tax uncertainty into the process.
After leaving Clifford Chance in 2022, Neidle founded Tax Policy Associates, a non-profit organisation that works with a network of tax and legal professionals to investigate tax avoidance, enforcement failures and systemic weaknesses in the UK tax system.
Rather than advising individual transactions, his work now focuses on evidence-based analysis for policymakers, journalists and institutions — bringing transparency to areas of tax risk that often only surface once deals are already done.
For dealmakers and advisers alike, his career arc reflects a broader shift in the profession: from clever structuring behind closed doors to accountability, defensibility and long-term risk awareness.
Dealmakers Advisory
Expert insight from the professionals shaping transactions before the market sees them.
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