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O4 & Partners
Jeroen Knol's O4 & Partners runs a Dutch multi-family office that combines investment deployment with in-house tax and legal execution from Maarssen.
O4 & Partners
Knol founded O4 & Partners in 2008 after building his career inside several private banks, embedding the firm from day one with what its website calls a 'no-nonsense private office' ethos. The office originally operated as a solo practice before a deliberate build-out that began in 2013, when Knol added an administrative company alongside the family-office advisory arm and relocated the combined operation to Buitenplaats Herteveld in Maarssen. That administrative unit handles the practical plumbing of wealth ownership — opening bank accounts, enrolling clients in private equity funds, producing quarterly reports — while the family-office side runs the investment and structuring decisions. The firm spans a deliberately wide set of asset classes. Its confirmed investment types include direct co-investments and SPVs, fund-of-funds commitments, private credit, secondaries, real estate, infrastructure, and intellectual property royalties. Stage coverage runs from seed through buyout and distressed situations, and the geographic mandate reaches Africa, Asia, Europe, the Middle East, North America, Oceania, and South America. Technology exposures are equally broad, with tagged interests ranging from AI/ML and enterprise software to space tech and Web3. This breadth suggests the office is aggregating client capital into diversified programs rather than concentrating on a narrow thematic bet. The firm operates from its current office at Schippersgracht 19 in the historic village center of Maarssen and was actively recruiting a financial assistant as of the most recent website update, indicating operational growth. Knol also serves as a lecturer for SRA, a Dutch professional network for accountants, teaching on fiscal and wealth management topics. In December 2025, business partner Olof Könst departed O4 & Partners to join Navis Private Office, a personnel move that shifts the firm's day-to-day relationship management closer to Knol and financial assistant Astrid van Hees. O4 & Partners combines investment deployment with in-house fiscal and legal structuring under one roof, a model that lets clients navigate Dutch tax-code complexity without outsourcing the coordination to a separate advisory firm. Multi-family offices often delegate those functions; O4 keeps them captive, which creates a stickier client relationship but also concentrates compliance risk inside a single small entity.
General information
Firm type
Multi Family Office
Year founded
2008
AUM
Undisclosed
Location
Region
Europe
Country
Netherlands
City
Maarssen
Corporate office
Schippersgracht 19, 3603 BC Maarssen, Netherlands
Principals
Jeroen Knol
Founder and Managing Partner
Astrid van Hees
Financial Assistant
Sector focus
Frequently asked questions
Who runs investment decisions at O4 & Partners?
Founder and managing partner Jeroen Knol leads the firm's investment strategy, drawing on more than a decade of private-banking experience before launching the office in 2008. The December 2025 departure of business partner Olof Könst has concentrated decision-making further under Knol, with financial assistant Astrid van Hees handling client-facing operational execution.
Does O4 & Partners commit to funds or only make direct investments?
The firm uses both approaches. Its confirmed investment types include fund-of-funds commitments, direct co-investments and SPVs, private credit, secondaries, real estate, and infrastructure, indicating a hybrid model that blends manager selection with direct exposure.
What investment stages does O4 & Partners cover?
The firm's stage coverage runs from seed through buyout, including growth-stage Series A to Series G rounds, distressed and turnaround situations, and intellectual property royalties. This wide span reflects a generalist program rather than a stage-specific mandate.
How does O4 & Partners handle the tax and legal side of wealth management?
Unlike many multi-family offices that refer clients to external law and accounting firms, O4 & Partners runs an in-house administrative company that handles bank account openings, private equity fund enrollments, quarterly reporting, and fiscal-juridical structuring. Founder Jeroen Knol also lectures for SRA on fiscal and wealth management topics.
Where does O4 & Partners invest geographically?
The firm's confirmed geographic reach extends across Africa, Asia, Europe, the Middle East, North America, Oceania, and South America. This global mandate is delivered through a mix of direct deals, fund commitments, and secondaries, though specific country-level allocations are not publicly disclosed.
What happened to Olof Könst and how does it affect the firm?
Olof Könst, formerly a partner at O4 & Partners, departed in December 2025 to join Navis Private Office. His exit left founder Jeroen Knol as the sole managing partner and moved day-to-day client relationship execution closer to financial assistant Astrid van Hees.
Is O4 & Partners a single-family office or a multi-family office?
It is a multi-family office. Jeroen Knol started the firm as a solo practice in 2008 and expanded it in 2013 by adding an administrative company and moving to a larger office, which allowed the firm to serve multiple families rather than a single founding wealth source.
Profile maintained by Altss using OSINT (open-source intelligence), regulatory filings, licensed data partners, and verified direct submissions. Read the methodology. Last updated: . Continuous refresh with full update cycles at least every 30 days.
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