A boutique practice

Bougainville Tax is a boutique tax advisory practice based in Rijswijk. We advise entrepreneurs, owner-directors, shareholders and high-net-worth individuals on domestic and cross-border tax matters, and we build long-standing relationships with clients who value personal, senior and expert counsel.

At Bougainville, every client has direct access to the senior advisor handling their file. No handovers, no intake team, no intermediate layers — from the first conversation to the final signature.

Our approach

Our way of working is calm, precise and focused on coherence. We assess every file from the full picture — a client's tax position rarely stands on its own, and good decisions require alignment between business and personal interests, between present and future, and between jurisdictions wherever they come into play.

We place equal weight on technically robust substantiation and on clear explanation. A tax advice is only valuable if the client can retell it, apply it, and defend it. We therefore devote as much attention to the analysis as to the way we report it — in plain language, with the legal sources alongside, and without unnecessary complexity.

Discretion is the norm. Our clients entrust us with their most personal and business-related wealth positions. We treat that information with the care it requires, and share nothing outside the circle of people necessarily involved in the engagement.

Expertise

Our expertise covers the full spectrum of Dutch taxation: income tax, corporate income tax, dividend withholding tax, box 2 and box 3, owner-director structures, real estate held privately and through a BV, wealth planning, estate planning and business succession. We prepare tax returns, opinions and litigation — both substantive and procedural.

We also have considerable experience in cross-border tax matters. When activities or wealth span multiple countries, we bring the relevant treaties, national legislation and group relationships together within a single consistent framework. We guide clients through emigration and remigration, international structures and transactions, and the alignment of tax positions across jurisdictions.

A particular place within our practice is held by the tax relationship between the Netherlands and Suriname. We advise individuals and companies with activities, investments or interests in both countries, and ensure — in collaboration with local advisors where necessary — alignment and coherence between the two jurisdictions. Within that corridor, oil and gas taxation is a core specialism: Siegfried Guillaume Kenswil is the author of the book ‘The Surinamese Production Sharing Contract’, the leading work on Suriname's PSC regime.

Who we work for

Our clients are entrepreneurs, owner-directors, shareholders and high-net-worth individuals who require high-quality, personal and discreet tax advice. Many operate in international contexts or move between jurisdictions. Others specifically seek a second, independent perspective on an existing position or an ongoing file.

What connects them is a shared preference for depth over volume, for long-term relationships over one-off transactions, and for a single senior point of contact over a diffuse team. For clients who wish to work in that way, we are the right address.

Why Bougainville

What sets us apart is no marketing formula. It is the way we work: senior, personal, technically robust, focused on coherence. No superficial advice, no handovers to juniors, no loss of overview. Every client has a direct line to the senior advisor handling the file, and the assurance that their tax position is fully overseen.

We are building a practice in which senior expertise reaches the client directly — scalable, but never at the cost of attention and judgement. Clients who work with us choose depth, long-term relationships, and a single point of contact who oversees their tax position in full.