Why the answer depends on the model
"Family office" describes at least three distinct arrangements: a dedicated team employed by one family (single-family office), a shared organization serving several families (multi-family office), and a coordinated advisor who handles investment management and works with the client's existing tax and legal professionals. Each carries a different cost structure, and the minimum that makes economic sense follows from that cost structure, not from a regulation or licensing requirement.
Single-family office: $100M and up
A single-family office means hiring your own team. At minimum, that typically includes a chief investment officer, a chief financial officer, and administrative and tax support — and often estate counsel and technology costs on top. Compensation alone for a small but qualified team can run from several hundred thousand to well over a million dollars annually before overhead, office costs, and professional liability.1
At $10M in assets, an advisory arrangement at 1% generates $100,000 per year — not enough to cover even one senior professional's compensation and benefits. At $100M, that same percentage generates $1,000,000, which is closer to viable for a lean team. The $100M threshold cited across the industry is a rough reflection of this arithmetic, not a regulatory rule.
Most families in the $5M–$30M range are not evaluating a dedicated single-family office. If a provider describes what they offer as a "single-family office" in this asset range, ask what the arrangement actually includes and who the team members are.
Multi-family office: no universal floor
A multi-family office shares its team and infrastructure across a small number of families, which lowers the overhead per client. Stated minimums vary considerably across firms that use this label — some require $20M or more in investable assets; others work with families starting lower if the relationship is a good fit.2
The minimum that matters most is not the stated threshold but the economics of the engagement: what will you pay per year, what will you receive, and how many other families share your lead professional's time? A firm where each partner works with five families looks different from one where the same person oversees fifty. Ask both questions directly of any provider you are evaluating.
Coordinated advisor: the common model for $5M–$30M families
Most families in the $5M–$30M range work with a fee-only registered investment advisor who handles investment management and financial planning, and coordinates — formally or informally — with the client's tax and legal professionals. Some advisors call this a "virtual family office" or "ensemble" model.3
Minimums here are lower because the overhead is lower. There is no internal legal department, no in-house tax preparation, no full-time CFO on staff. Advisors in this space typically quote investment minimums ranging from $1M to $5M or more depending on the depth of service, and many combine an asset-based fee with retainer or project charges for planning work outside investment management.
This is not a compromise arrangement — for most families in the $5M–$30M range, it is the right answer. A well-structured coordinated engagement can cover investment management, tax-aware planning, estate coordination, insurance review, and multi-generational planning without the overhead of a dedicated team.
What actually drives the number up
Complexity pushes toward a more intensive model more reliably than asset level alone. A family with $8M spread across a business interest, two trusts, and accounts in multiple jurisdictions may need more coordination than a family with $20M in a straightforward brokerage account. Factors that typically call for more structure include:
- Multiple legal entities or trusts. Each adds coordination overhead and requires clear responsibility for reporting, distributions, and compliance filings.
- An active business or expected liquidity event. A pending business sale, equity payout, or inheritance introduces time-sensitive tax and legal decisions that benefit from tight advisor coordination.
- Concentrated positions. A large block of employer stock, real estate, or private equity requires specific planning around valuation, diversification timing, and tax exposure.
- International accounts or income. Foreign asset reporting and cross-border income add compliance work that not all advisors are equipped to handle.
The practical question
Rather than asking whether you meet a minimum threshold, start with your actual decisions: what coordination is currently unresolved, and who handles each part of it? That list — not the $100M figure in a marketing document — defines what you need from a provider and whether the overhead of a more intensive model is justified for your situation.
For most families in the $5M–$30M range, a coordinated advisor who understands the full picture is both available and the right fit. The comparison worth making is between specific written proposals, not model labels.
Sources & further reading
Source pages reviewed September 2026. Dollar ranges cited are illustrative; actual fees and minimums vary by firm and engagement.