After 34 years at Aon, Marguerite Soeteman-Reijnen has built one of the most consequential supervisory portfolios in the Netherlands. What she chooses next will continue to shape Dutch boardroom diversity.
When Marguerite Soeteman-Reijnen retired from Aon Holdings on April 1, 2024, the assumption in much of the Dutch business press was that she was stepping back. Almost 35 years inside one of the largest professional services firms in the world. Chairman of the Executive Board since 2016. Global Chief Marketing Officer of Aon Inpoint. A career that had carried her from her first role as a young lawyer at Erasmus University to representing the Kingdom of the Netherlands at G20 Ministerial Conferences in Italy, Indonesia and India. The conventional expectation was a soft landing into a few advisory roles.
What has happened ever since is something quite different. Soeteman-Reijnen has built a post-executive portfolio that few in the Netherlands match. The combination is rare. Independent Non-Executive Director at Siemens Nederland since October 2023. Vice Chairman of the Supervisory Board at international law firm NautaDutilh until recently. Former Chairman of the Supervisory Board at Kelp Blue. Member of the Supervisory Board at MN, theDutch pension asset manager, as Chair of the Audit Committee since January 2025, following approval by De Nederlandsche Bank. Advisory Board member at RESiLICON in Groningen. And, since March 2026, Non-Executive Director at the Hanseatic Broking Center, the Hamburg-based insurance brokerage platform recently valued at over 800 million dollars.
The HBC appointment is the most strategically interesting of the recent additions. HBC, founded in 2022 and backed by London-based private equity firm Bridgepoint is a consortium of owner-managed insurance brokers expanding rapidly across European markets. The company has just completed a successful expansion into the Nordic market and is consolidating its position in occupational pensions and health insurance.
Gert Schlossmacher, CEO of the HBC Group, framed her appointment in terms that explain the strategic logic. The combination of with international brokerage expertise was exactly what HBC needed for its next phase of development. Soeteman-Reijnen herself was direct about her reading of the platform. HBC, she noted, had built an impressive platform in a short period of time. Her contribution would be to support the group’s further scaling and integration within European markets.
The appointment matters beyond HBC. Few Dutch executives carry the combination of seniority, sector expertise and international authority that allows them to be hired as Non-Executive Director by a private equity-backed European platform during its scaling phase. The credibility that the role requires is built over decades, in environments where the executive has to navigate listed-company governance, regulatory complexity, and cross-border integration simultaneously. Soeteman-Reijnen’s 34 years at Aon, ending with the chairmanship of Aon Holdings, prepared her for exactly this kind of work.
The other strand of her post-executive work is more publicly visible. Since 2021, Soeteman-Reijnen has been Chair of the Advisory Board of SER Topvrouwen, the Dutch nationwide initiative that maintains the database of board-ready women and monitors gender balance in the (sub)top of Dutch corporate life. In December 2025, she formally transitioned from the Advisory Board to the role of ambassador, alongside Mariette Hamer, Petri Hofsté and Janine Vos, as the SER restructured its diversity portfolio for 2026.
The role carries direct institutional weight. The annual SER Scorecard, presented to the Deputy Minister of OCW, is the single most authoritative measurement of Dutch boardroom gender balance. In March 2026, the Scorecard reported that 17.3% of executive board seats and 26.1% of supervisory board seats in large Dutch companies were held by women. Within financial services, the figures rose to 24.2% and 36.9% respectively. Within technology, they fell to 12.4% in the C-suite. These are the numbers that shape policy.
Soeteman-Reijnen’s framing of diversity has been consistent and notably commercial. She has argued for years that gender balance is a business question rather than a fairness question. Companies that embrace diversity, in her phrasing, reap the rewards in workforce agility. The 4,300 board-ready women now in the SER Topvrouwen database are not, in her framing, a pool of qualified candidates to be promoted out of obligation. They are an underused commercial asset.
A career like Soeteman-Reijnen’s is built, in part, on a particular kind of educational discipline. She received her Master’s degree in Law from Erasmus University Rotterdam in 1990. She subsequently completed programmes at INSEAD, Harvard Business School and IMD. In 2022, RAI University in India conferred an honorary doctorate in philosophy on her work in diversity, leadership and the insurance industry. The combination of Dutch legal foundation, international business school exposure and academic recognition is unusual for a Dutch executive of her generation.
What it signals is something the SER Topvrouwen position makes explicit.The senior women now reaching boardroom roles in the Netherlands are increasingly those whose educational architecture was built deliberately, overdecades, with international components woven in at every stage.
Twenty-eight roles on a LinkedIn profile is a striking number. What matters is the shape of the portfolio rather than its size. Soeteman-Reijnen’s current supervisory and advisory roles cluster around three themes. The first is regulated complexity, which is the domain of Siemens, MN and HBC. The second is sustainability and impact, which is where Kelp Blue and the Dutch Royal Military Museums sit. The third is institutional Dutch diversity, embodied in SER Topvrouwen and her ambassador roles.
The portfolio is, in other words, a deliberate architecture. It is built on those companies where Marguerite with her skills and background can add value, make a change and impact. It is not a collection of comfortable retirement seats. It is also a working structure designed to maximize the influence of the next decade of her career. The Dutch boardroom landscape benefits from this kind of deliberate construction. The women who build similar portfolios in the years ahead will shape the supervisory and advisory layer of Dutch corporate life for the rest of the decade.
The lesson worth holding onto is not that any specific role on Soeteman-Reijnen’s CV is replicable. It is that the architecture of a senior leader’s portfolio can be built consciously, rather than accumulated incidentally. The choice of which boards to join, which sectors to span, which institutional bodies to support, can be made strategically. Done well, it produces what Soeteman-Reijnen has demonstrated. A post-executive presence that is more, not less, consequential than the executive role that preceded it.
Marguerite Soeteman-Reijnen is, since 2025, an active member and Ambassador of Leading Ladies Business Club, joining a circle of exceptional women. The decision to associate her name with the Leading Ladies Business Club reflects what the architecture of her career has long demonstrated. That sustained influence at the highest level is built, not granted, and that the women who construct it deliberately shape the institutions they touch.
Sources:
HBC Group press release (March 2026)
Hanseatic Broking Center company profile (PitchBook, May 2026)
Management Scope (January 2025)
SER jaaroverzicht 2025
SER Topvrouwen profile
Erasmus Trustfonds (2024)
Rise& Lead Women profile
WEF / Infosys Leadership Summit biographies
BusinessInsurance Woman to Watch (2010)
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