A single-family office (SFO) serves one family exclusively, offering maximum control and privacy at a high fixed cost. A multi-family office (MFO) serves several families, sharing professional infrastructure to lower cost and widen access, in exchange for less exclusivity and customisation.
Families with substantial wealth face a structural choice: build a private organisation that serves them alone, or join one that serves several families at once. The first is a single-family office (SFO); the second is a multi-family office (MFO). Both manage investments, tax, estate planning and administration with professional rigour, but they trade off cost, control, privacy and scale in opposite directions. Choosing between them is one of the defining decisions in the management of large private wealth.
What is a single-family office?
A single-family office exists to serve one family exclusively. It employs its own investment professionals, lawyers, accountants and administrators, and every decision is made solely in that family's interest. Nothing is shared, nothing is diluted, and the strategy is built entirely around the family's goals — whether that is preserving capital across generations, supporting a family business, or pursuing a particular investment philosophy.
The appeal is control and alignment in their purest form. The family sets the mandate, owns the infrastructure, and keeps its affairs entirely private. The drawback is cost: the family carries the full expense of staff, systems and compliance, which is why a dedicated SFO is generally only economical above roughly $100-250 million in assets, and often considerably more.
What is a multi-family office?
A multi-family office provides the same range of services — investment management, tax and estate planning, reporting, philanthropy, administration — but to several unrelated families at once. By spreading the cost of professional staff and infrastructure across multiple clients, an MFO delivers institutional-quality management at a fraction of the cost of building it alone.
The trade-off is exclusivity. An MFO's attention, customisation and confidentiality are shared among its clients rather than dedicated to one. In return, families gain access to capabilities — specialist managers, private-market deals, sophisticated reporting — that they could not justify funding on their own. The multi-family office sector has grown into a significant industry in its own right: global MFO assets have surpassed $5.2 trillion, according to research from With Intelligence by S&P Global tracking more than 1,600 firms, with consolidation accelerating as larger firms acquire smaller ones.
The core trade-offs: cost, control, privacy and scale
The decision between the two models comes down to four levers.
Cost. A single-family office carries its entire overhead; a multi-family office shares it. For all but the largest fortunes, the MFO is the cheaper way to access the same expertise.
Control. An SFO gives the family complete authority over strategy, staffing and confidentiality. An MFO requires accepting standardised processes and shared priorities.
Privacy. A single-family office keeps the family's affairs entirely in-house. A multi-family office, however discreet, involves disclosing information to a firm that serves others.
Scale and access. Counter-intuitively, an MFO can sometimes offer better access than a small SFO. By pooling the assets of many families, it negotiates lower fees, reaches managers with high minimums, and sources co-investment opportunities that a single modest family office could not. A very large SFO enjoys the same advantages on its own; a small one may not.
When does each model make sense?
A single-family office tends to make sense for families whose wealth comfortably justifies the fixed cost and who place a high value on control, privacy and a strategy designed solely around them. These are typically the wealthiest families, often with an operating business or complex cross-border affairs that demand dedicated, bespoke management.
A multi-family office suits families who want professional, institutional-grade management without the burden of building and running it themselves. That includes families whose wealth — while large — does not justify a full SFO, those who prefer to outsource operations, and those who value the shared access to managers and deals that pooling brings. Many families also use an MFO as a stepping stone, graduating to a single-family office only when their wealth and complexity grow.
It is not always either/or. A growing number of families run a lean single-family office focused on governance and oversight while outsourcing investment management or specific functions to a multi-family office — blending the control of the first model with the shared scale of the second. This hybrid sits close to the logic of the outsourced chief investment officer, where a family or institution keeps strategic control but delegates day-to-day portfolio management to a specialist provider.
How an MFO differs from a private bank
Families sometimes ask why they would use a multi-family office rather than simply bank with a large private bank. The distinction matters. A private bank's core business is selling financial products — its own and its partners' — to wealthy clients, and its advice sits within that commercial model. A multi-family office is typically more independent and more holistic: it coordinates investments, tax, estate planning, philanthropy and administration across whichever providers best serve the family, and its revenue usually comes from advisory fees rather than product sales. The MFO's value lies in objective oversight of the whole picture, not in distributing products.
In plain English
A single-family office is a private firm built for one family — total control and privacy, at full cost. A multi-family office is a shared firm serving several families — lower cost and often wider access, at the price of exclusivity. The wealthiest families build their own; most others share, and many do a bit of both. The right answer turns on how much a family is willing to pay for control, and how much scale it can bring to the table.
Sources and further reading
- InvestmentNews / With Intelligence by S&P Global — global multi-family office assets surpassing $5.2 trillion across 1,600+ firms.
- With Intelligence, Single Family Office Asset Pools 2025 — SFO scale and economics.
- Deloitte Private, Family Office Insights Series — single- and multi-family office structures and growth.