What Changes When A Family Office Starts Managing Outside Capital?
A family investment platform built around one family operates under a different set of pressures from an asset manager serving unrelated clients. The family can tolerate concentrated positions, accept long holding periods, support investment themes linked to its values and judge performance against objectives that outsiders never see. Once external investors enter the structure, those preferences have to coexist with separate mandates, reporting requirements and legal duties.
The Brenninkmeijer family offers a current example. Through COFRA, the family behind C&A has built an investment organisation spanning asset management, private equity and real estate. Anthos Fund & Asset Management, which manages money for the family office as well as outside investors, now forms part of a broader growth strategy. COFRA has stated an ambition to lift assets under management from roughly €35 billion to €70 billion by attracting other family offices, foundations and large investors.
Anthos is not the Brenninkmeijer family office itself but the asset manager that serves the family alongside external clients. This is important to know because the organisation already sits beyond the traditional single-family-office model. In 2022, Anthos opened its investment platform to outside asset owners after decades of managing capital linked to the Brenninkmeijer family and its associated organisations.
Its next phase shows what happens when investment infrastructure built around one family becomes a commercial business.
Scale Changes The Economics
Family offices are expensive organisations to run. Investment staff, reporting systems, legal work, compliance, due diligence and access to specialist managers all carry fixed costs. Campden Wealth found average annual operating costs of about US$2.6 million for European family offices below US$500 million in assets, US$4.2 million for those between US$500 million and US$1 billion, and US$10.1 million for offices above US$1 billion.
The cost burden falls sharply as assets rise. Campden estimated operating costs at around 105 basis points for smaller offices and 36 basis points for the largest. A family that already pays for institutional investment infrastructure therefore has an economic reason to put more assets through it.
Outside capital changes the equation again because additional assets generate fee income. Staff, systems and manager relationships no longer serve only the owner. The family starts selling access to an investment organisation that already exists.
The addressable market has also grown. Deloitte estimated around 8’030 single-family offices worldwide in 2024, up from 6’130 in 2019, with aggregate assets under management of roughly US$3.1 trillion. Deloitte expects that figure to reach around US$5.4 trillion by 2030.
More family wealth therefore sits inside dedicated investment organisations that need managers, private-market access, reporting infrastructure and specialist expertise. Family-backed asset managers now compete for that capital alongside banks, traditional asset managers and multi-family offices.
One Owner Becomes Several Clients
A family office ultimately answers to one ownership system, even when several generations and family branches disagree. External clients introduce separate economic interests.
Imagine the investment team finds a private transaction with room for €250 million. The founding family wants €200 million and external clients want another €150 million. The investment committee no longer faces only an investment decision. Someone has to decide how the allocation gets divided, whether the family receives priority and whether every client invests on identical terms.
Scarce fund capacity creates the same issue. So do co-investments, liquidity events and access to specialist managers.
A family owner might accept preferential access as part of ownership. An external client paying management fees expects the manager to explain how allocations work before a conflict arises. Formal policies replace assumptions that once depended on personal relationships.
Anthos already acknowledges differences between proprietary assets and segregated client mandates in its responsible-investment framework. Separate mandates carry their own requirements, exclusions and investment objectives. An organisation managing outside capital therefore stops treating the portfolio as one pool of money governed by one set of preferences.
Performance Needs A Common Language
Families rarely define investment success through return alone. One family might tolerate a large exposure to an industry it knows well. Another might accept lower expected returns from investments that align with religious or environmental principles. A founder might keep shares in a business for strategic or emotional reasons despite the concentration risk.
External investors bring their own objectives. A foundation board has to judge whether the manager followed its mandate. A family office client might compare Anthos with other managers. An institutional investor needs performance attribution, risk measurement and documented investment decisions.
Those demands change internal behaviour. Investment teams have to explain why a strategy exists, how much risk it carries, what benchmark fits it and under which conditions the organisation exits. Historical preferences no longer provide enough justification.
Institutional scrutiny also exposes weak practices. Families sometimes retain managers, structures or asset allocations because earlier generations chose them. External clients have no reason to accept history as an investment thesis.
Reporting therefore becomes part of investment management rather than an administrative layer around it. The organisation has to demonstrate how decisions produced returns, losses and portfolio risks.
Asset Gathering Adds A Second Objective
A family investment office exists to manage capital. A commercial asset manager also needs to attract and retain clients.
Suppose an investment strategy has room for €2 billion before additional capital starts weakening returns or reducing access to attractive transactions. The investment team wants to stop at €2 billion. The commercial organisation earns more revenue if assets reach €3 billion.
Product design starts carrying the same tension. Clients often prefer strategies that fit familiar allocation categories and reporting formats. A family might have built part of its own wealth through concentrated holdings, unusual private investments or very long holding periods. Those investments are harder to package into a product for external clients.
Hiring priorities move as well. A platform serving one family needs investment specialists. A platform selling mandates also needs client reporting, compliance, distribution, relationship management and legal resources.
Anthos’ choice of leadership reflects that institutional direction. Ronald Wuijster, appointed chief executive in 2026, previously led the investment arm of Dutch pension provider APG. APG managed around €600 billion. COFRA’s own target of about €70 billion therefore places Anthos under a chief executive who spent years inside an organisation almost an order of magnitude larger.
The appointment brings experience from an environment where investment mandates, governance, reporting and client obligations form part of everyday portfolio management.
Outside Capital Also Improves Discipline
Commercialisation does not automatically weaken the family model. External clients often force an investment organisation to become more precise.
A manager serving unrelated investors needs clear allocation rules, formal risk limits, stronger reporting and documented investment processes. More assets also support larger specialist teams, better systems and access to managers that one family might struggle to justify on cost alone.
COFRA presented part of the logic in similar terms when Anthos opened the platform to other asset owners. Pooling capital creates scale, while working with outside investors exposes the organisation to other institutions’ investment practices.
The founding family also benefits from scrutiny that it did not impose on itself. External clients ask why a mandate exists, how performance compares with alternatives and whether a portfolio still matches its stated objective. Those questions force managers to separate investment conviction from inherited habit.
The benefits disappear if commercial growth starts overriding investment discipline. A family-backed manager that gathers assets faster than its strategies absorb them has recreated one of the standard conflicts of the asset-management industry inside an organisation originally built to avoid short-term commercial pressure.
Ownership And Client Duties Need A Clear Boundary
A family-backed asset manager carries the family name, capital and history while serving investors whose interests remain separate from those of the owner.
Clients need to know whether they invest alongside the family, hire an independently run asset manager owned by the family or enter a structure where family capital receives different treatment. Fees, allocation rules, voting rights, liquidity and access to investments all depend on that answer.
The founding family also needs to decide what it wants from the business. Fee income offers one objective. Better infrastructure for the family’s own capital offers another. Building a standalone asset manager introduces a third.
Anthos shows how far the model can travel. COFRA wants to double managed assets towards €70 billion while keeping the investment organisation connected to the Brenninkmeijer family. External family offices, foundations and institutions become clients rather than participants in the family’s own governance structure.
The organisation therefore has to do two jobs at once. It remains owned by a family, carries the family’s history and often invests alongside it, while owing professional duties to clients whose capital comes with separate objectives.
Outside money does more than enlarge the asset base. It forces the family to decide which privileges belong to ownership and which rules apply equally to every investor.
What Family Offices Need To Get Right Before Taking Outside Capital
Set allocation rules before the first conflict. Decide how scarce private deals, fund capacity and co-investments are divided between family capital and external clients.
Separate ownership privileges from client treatment. The family may own the manager, but paying clients need clear terms on fees, access, liquidity, voting rights and investment opportunities.
Define the capacity of each strategy. Asset gathering should stop where additional capital starts weakening expected returns or access to deals.
Formalise what used to be understood informally. Document mandates, benchmarks, risk limits, exclusions, exit rules and reporting standards rather than relying on family history or personal relationships.
Build the commercial organisation around the investment strategy, not the reverse. Distribution targets, product design and client demand should not force the investment team to deploy more capital than a strategy can absorb.
Use external scrutiny to improve the family’s own investment platform. Client reporting, performance attribution, compliance and governance can expose practices that survived mainly because nobody had challenged them.
Decide what the business is meant to become. A family needs to know whether external capital exists to support its own investment infrastructure, generate fee income or build a standalone asset manager. Each objective leads to different hiring, governance and growth decisions.
