Single Family Office vs Multi Family Office: The Honest Trade-Offs

Within a year of the wire landing, every newly liquid founder hears the same sentence: "At your level, you should really have your own family office." It is delivered as a compliment. It is also, on close inspection, a proposal that you fund a small financial institution out of your own pocket, staff it, govern it, and carry its key-person risk — indefinitely.

The single family office versus multi family office question is usually framed as a matter of status, as though the SFO were the business-class cabin and the MFO the seat behind the curtain. That framing suits everyone who sells either structure. It does not suit the family. Stripped of flattery, the choice rests on three things: arithmetic, control, and people. All three can be examined honestly. Almost nobody does.

What a single family office actually costs

Start with the numbers the industry itself publishes, because they are more sobering than the brochures.

The headline range. UBS's Global Family Office Report 2025 — drawn from 317 family offices with an average net worth of $2.7 billion and average office assets of $1.1 billion — put the average cost of operating a family office at between 0.35% and 0.44% of assets a year. Citi Wealth's 2025 Global Family Office Report, surveying 346 offices with an average family net worth of $2.1 billion, found a similar spread: 36% of offices spend under half a percent of assets annually, another 36% spend between 0.5% and 1%, and 15% spend more than 1%.

The scale trap. Look closer at the UBS data and the inconvenient part emerges. Offices managing between $100 million and $250 million spent roughly 0.42% of assets; so did those up to $1 billion. Only above $1 billion did the average fall to 0.35%. The economies of scale that make a family office cheap arrive at precisely the point where almost no family is. And the global surveys skew large — they are samples of bank clients with ten-figure balance sheets. Deloitte's 2026 study of the Hong Kong market, one of the few to examine ordinary-sized offices closely, put single family office running costs at 0.64% to 1.11% of assets. For a $150 million family, the honest planning number is not the 0.35% achieved by billion-dollar offices. It is something closer to double that — call it $1–1.5 million a year, every year, before a single investment fee is paid.

None of this says the SFO is a bad structure. Deloitte's global research counted 8,030 single family offices worldwide in 2024, up from 6,130 in 2019, and projects more than 10,720 by 2030. Families keep building them for reasons the spreadsheet cannot capture. But the spreadsheet should at least be opened first.

What a multi family office is — and what it honestly charges

A multi family office is a professional firm that runs the family-office function — investment management, consolidated reporting, tax and estate coordination, sometimes concierge administration — for several families at once, mutualising the costs no single family wants to carry alone. The better ones grew out of actual single family offices that opened their doors; the weaker ones are wealth managers who discovered the phrase commands higher fees.

The fee structure. Most full-service multi family offices charge an asset-based fee, typically tapering with scale, with fixed annual retainers layered on for tax, legal and administrative work. Industry fee guides cluster the asset-based component between half a percent and one percent of managed assets, and the direction of travel is downward: Cerulli Associates projects that by 2026 the average advisory fee for clients with more than $5 million will settle near 76 basis points, with most advisers already conceding lower pricing at the top end. For a $150 million family, a well-negotiated MFO relationship can cost meaningfully less than the office it replaces — with the institution, not the family, carrying the staffing risk.

The honest trade-offs. They are real, and an adviser pitching an MFO will rarely volunteer them. You are a client, not the principal — one of perhaps thirty or fifty families, and not necessarily the largest. The word "bespoke" does a great deal of lifting in MFO marketing; in practice, model portfolios exist because they must. Conflicts of interest need auditing: some MFOs earn placement or product revenue on top of stated fees, which is precisely the behaviour the structure was supposed to escape. Response times are institutional, not familial. And confidentiality, while contractually robust, is structurally different when thirty families share one operations team.

The fair summary: the MFO buys you continuity, infrastructure and peer-tested process at a price a single family could not replicate — in exchange for standing in a queue you do not control.

The threshold everyone quotes, and why it answers the wrong question

Practitioners commonly cite $100 million in investable assets as the floor at which a single family office becomes defensible, and $250 million as the level at which the economics become comfortable — the point where a full investment team can be carried at well under 1% of assets. Those numbers are folklore with a basis in fact, and the cost data above broadly supports them.

But the threshold question — am I big enough? — is only half the decision, and arguably the smaller half. Complexity is the better predictor. A $400 million family whose wealth sits in listed securities and a handful of fund commitments has little that justifies a dedicated office; an MFO or even a disciplined private bank relationship will serve them well at a fraction of the cost. A $120 million family with two operating businesses, property in three jurisdictions, NRI members with cross-border tax exposure and a direct-investment appetite has complexity that no shared platform handles gracefully — whatever the AUM threshold says.

The honest test is not the size of the fortune but the shape of it. Offices exist to absorb complexity. If yours is simple, you are buying an institution to manage a brokerage account.

Talent is the decision, not a line item

Here is the number that should dominate the conversation and almost never does. In the UBS 2025 survey, staff costs accounted for 67% of core family office operating expenses — by far the largest line, and rising. When you choose a single family office, you are not primarily choosing an investment structure. You are choosing to become an employer in one of the most competitive talent markets in finance.

Consider what the Citi survey reveals about how that contest is going: 45% of family offices have no chief investment officer at all. The reasons are structural, not accidental. A first-rate CIO can earn more at a fund, with carry, a team and a career path. A single family office offers one client, one boss, and a promotion ladder with no rungs. The families that solve this do so with genuine economics — co-investment rights, long-term incentive plans — which pushes the true cost of the office well beyond the survey averages.

And once you have hired well, you have created a new fragility: the office now depends on the person you fought to recruit. J.P. Morgan's 2026 family office research found that 86% of offices have no succession plan for their own key decision makers — a problem we examined at length in key-person risk inside the office. The MFO's strongest honest argument is precisely here: when its CIO resigns, that is the firm's problem. When yours resigns, it is your Thursday.

The third way that is quietly winning

The binary framing — build everything or buy everything — is increasingly false. Look at what family offices actually are, rather than what the term evokes: in the Citi survey, 39% run on one to three employees, and nearly two-thirds on six or fewer. The median family office already looks less like the Rockefeller suite and more like a small, senior, partly outsourced team — a structure the industry has taken to calling the hybrid or virtual family office.

The pattern is consistent: a lean in-house core — typically a trusted CFO-type and an executive assistant who together hold the family's full picture — wrapped around outsourced specialists. Investment management goes to an external or fractional CIO; custody, reporting and consolidation to a platform or MFO; tax and legal to retained firms. The family keeps what genuinely requires loyalty and context. It rents everything that does not.

India's family office boom is, in practice, largely a hybrid boom. PwC counts roughly 300 family offices in India in 2024, up from about 45 in 2018 — a sevenfold rise in six years — and the typical new office is not a forty-person institution but a small professional core professionalising what the promoter's personal staff once did informally. For families weighing the structural choices in an Indian regulatory context, we cover the ground separately in setting up a family office in India.

The hybrid model has its own honest weakness — coordination. Someone must own the whole picture, or the family ends up with five excellent vendors and no strategy. But as a starting position it has a virtue neither pure model offers: it is reversible. You can grow an in-house team as complexity grows. Unwinding a fully staffed office, with its severance, its leases and its awkward conversations, is a project families undertake exactly once.

The question your peers can answer and your advisers cannot

Every adviser in this market has a structural preference, because every adviser has a revenue model. The private bank would rather you did not build an office. The MFO would rather you joined theirs. The lawyers and recruiters would rather you built your own, elaborately. All of them are honest people; none of them is a disinterested one.

The people without a position are the families who have already made the choice — and lived with it for a decade. What did the office actually cost against what was projected? Which functions turned out to be worth owning, and which became expensive furniture? Who regretted building, and who regretted waiting? These are the conversations that happen inside SoHo's member network precisely because they cannot happen across an adviser's desk: principal to principal, with no structure to sell and the numbers spoken out loud.

The right structure is not the one that flatters the size of the fortune. It is the one the family is still quietly glad of ten years on, when nobody is looking, and nothing needs to be signalled.