The question ultra-high-net-worth families ask immediately after a liquidity event is usually the wrong one. "Should we start a single-family office?" presumes the answer is a function of wealth. The data from J.P. Morgan's 2026 Global Family Office Report, drawing on 333 single-family offices across 30 countries with an average net worth of $1.6 billion, suggests the more important variable is operational readiness, and most families, regardless of asset size, do not have it.1
The Cost Threshold Is Clearer Than People Expect
Operating costs scale substantially with AUM: offices managing $250 million or less average approximately $875,000 per year; offices managing $250 million to $500 million average $1.7 million; offices managing $500 million to $1 billion average $3.2 million; and offices managing more than $1 billion average $6.6 million, per J.P. Morgan's 2026 report.1
The practical threshold at which a dedicated single-family office becomes economically rational generally begins at $100 million to $250 million in investable assets.2 Below that band, the math tilts toward a multifamily office arrangement: an MFO is almost always less expensive on an absolute basis because staff, technology, and infrastructure costs are spread across multiple client families, with MFOs typically charging 0.50% to 1.00% of assets under management plus retainers of $25,000 to $250,000 per year.2
The cost comparison, though, is only the first cut. Families that treat AUM as the sole deciding variable tend to learn the harder lesson later.
The Governance Gap Is Where the SFO Model Breaks Down
As family enterprises grow more complex, governance is becoming a critical tool for managing both risk and relationships. Yet 86% of global family offices do not have clear succession plans in place for decision makers, per J.P. Morgan's 2026 report.1
That figure applies to established offices with substantial assets and professional staff. It is not a startup problem. Beyond cost, a single-family office requires governance infrastructure: without clear decision-making processes, delegation structures, and accountability mechanisms, the autonomy that makes a single-family office attractive can become a risk, enabling ad hoc decision-making, concentration of authority in one individual, or insufficient oversight of staff and service providers.3
Overreliance on a single individual or provider was flagged as one of the most commonly cited risks to long-term effectiveness in J.P. Morgan's 2026 report.1 The SFO's concentration of authority, which is the feature that makes it appealing in year one after a liquidity event, is precisely what creates fragility at the first generational transition.
Notably, 80% of family offices outsource some aspect of their portfolio management, and one-third of offices with $1 billion or more outsource more than half of their portfolios, per the same survey.1 The SFO, in practice, is rarely as self-contained as the brochure implies.
What the Structure Decision Is Actually About
A common trajectory begins with a multifamily office or outsourced arrangement in the early years after a liquidity event, transitions to a hybrid model as the family develops governance capacity and investment sophistication, and may eventually mature into a full single-family office as asset growth and complexity justify the investment, per Morgan Lewis's July 2026 analysis.3
That sequencing reflects something the cost comparison misses: governance capacity is built, not purchased. A family that has never operated a collective investment structure, managed a professional staff, or navigated intra-family disagreements over capital allocation is not ready to run a single-family office on day one, regardless of the proceeds from the liquidity event. The governance infrastructure has to develop alongside the wealth.
The multifamily office and the registered investment adviser serving UHNW families do something the SFO cannot do in its first years: they provide the structure, reporting, and decision-making discipline the family has not yet built internally. The access question (who gets onto cap tables, who sources the right private deals) matters too, and that is a function of the adviser's institutional relationships, not the legal form of the family office entity.
The structural question, SFO versus MFO, is ultimately a question of readiness: whether the family has the governance, the talent pipeline, and the internal decision-making capacity to justify the fixed cost. The J.P. Morgan data suggests that even families which have already made that commitment are, by a wide margin, still working on it.1