The Mid-Sized Family Office, Illustrated

What "Mid-Sized" Means in Practice

A family office at this scale typically sits between the scrappy lean family office and the fully staffed institutional office. The headcount — commonly six to fifteen people — reflects a family whose financial life has grown complex enough that one or two generalists can no longer cover everything, but not so large that it needs an internal legal department or a dedicated trading desk.

The trigger for this build-out is rarely a single event. More often, a founder who sold her logistics company finds that three years after liquidity, she is managing a portfolio of private funds, two operating real estate partnerships, a private foundation, trusts for four children, and a household staff of twelve. The volume of decisions, reporting, and compliance work simply exceeds what a small team can absorb.

Importantly, there is no universal definition of a mid-sized office and no net-worth threshold that mandates this structure. Families arrive here based on complexity, not a number.

The Org Chart: People, Roles, and Reporting Lines

The table below shows a representative mid-sized office. Headcount and titles vary; the point is to illustrate how functions are distributed, not to prescribe a single correct structure.

A three-generation family with two operating businesses might add a philanthropy director or a dedicated estate manager if property holdings warrant it. The core structure above, however, covers the vast majority of mid-sized offices.

The Principal and Family Board

The principal — or a small family board where multiple generations hold authority — sits above the operating team. This layer does not manage day-to-day work; it sets the mission, approves the Investment Policy Statement, authorizes large capital allocations, and resolves decisions that cross the authority of any single employee.

Formalizing this layer matters more than most families expect. Without clear boundaries between family governance and staff operations, the managing director spends energy seeking approval for routine decisions, and important strategic questions go unanswered. Families commonly document these boundaries in a family constitution or a written governance framework. Qualified attorneys should be involved in drafting any such documents, particularly where trusts or fiduciary roles are implicated.

Decision Rights: Who Can Approve What

One of the structural advances a mid-sized office makes over a lean one is a written approval matrix — a document that maps decision types to authority levels. Without it, a six-person team wastes significant time escalating decisions that could be handled at the staff level, while genuinely significant commitments slip through without principal review.

A common illustrative pattern (not a recommendation) might look like this:

• Routine operating expenses up to an illustrative threshold — approved by Controller or CFO without further sign-off.
• New manager relationships or fund commitments below a set size — approved by CIO after Investment Committee review.
• Capital calls or co-investments above a set size — require Managing Director and Principal sign-off.
• New legal entities, trust amendments, or philanthropic commitments — always escalate to the Principal or Family Board.
• Wire transfers above a defined amount — require dual control, meaning two authorized staff members must independently approve.

The specific thresholds are set by each family based on their own circumstances. The structure of the matrix matters more than the numbers. Families must work with qualified attorneys and CPAs when decision rights touch legal authority, fiduciary duty, or tax consequences.

The Committees That Appear at This Scale

A lean office often operates informally — the CIO and the principal talk, a decision gets made. At mid-size, two or three formal committees commonly emerge.

Investment Committee

The Investment Committee is the most common formal body at this scale. It typically includes the CIO, the Managing Director, the principal or a family representative, and occasionally an outside advisor. The committee reviews proposed allocations, monitors asset allocation against the IPS, and approves manager additions or removals. Meetings are documented with minutes, which creates an audit trail and supports the family's governance record.

Finance and Operations Review

Many mid-sized offices hold a recurring finance meeting — monthly or quarterly — where the CFO or Controller presents a consolidated report covering net worth, liquidity, entity-level performance, and any unusual items. The Managing Director and relevant family members attend. This is not a board meeting; it is an operational rhythm that keeps the family informed without creating decision bottlenecks.

Philanthropy Committee

Where the family has a donor-advised fund or private foundation, a philanthropy committee — sometimes just the principal, a family member from the next generation, and a staff coordinator — meets to review grant requests and giving strategy. This committee often becomes an important vehicle for next-generation engagement with the family's values.

Outside Specialists: What Stays External

Even a fifteen-person office typically keeps several functions external. This is a deliberate choice, not a gap. Outside counsel handles entity formation, trust drafting, and litigation risk — matters where legal liability and specialization argue strongly for an independent expert. A CPA firm handles tax return preparation and may coordinate estimated payments, though the internal tax director, if the family has one, owns the overall tax strategy.

Risk and insurance advisors, cybersecurity specialists, and sometimes an outsourced CIO for a specific sleeve of the portfolio are also commonly kept external. The internal vs. outsourced decision at each function turns on cost, confidentiality, and how often the expertise is actually needed. Readers exploring this tradeoff should review when a family office makes economic sense alongside the specific function in question.

How This Differs from a Lean or Institutional Office

Compared to a lean office, the mid-sized structure introduces formal titles, defined reporting lines, and written governance — things that feel unnecessary when two people can simply talk. The cost is higher, but so is the capacity to manage complexity, run multiple asset classes, and sustain operations if a key person leaves.

Compared to an institutional office, the mid-sized office still relies heavily on external specialists for legal and tax work, does not have a dedicated trading infrastructure, and typically lacks a full-time general counsel or a compliance officer. The jump from mid-sized to institutional is as much a governance and cultural shift as a headcount one.

Families considering whether this model fits their situation will find the comparison in family office examples and structures useful, alongside a clear-eyed look at what a family office costs at different scales.