Family offices in the $200M–$2B AUM range face a genuine governance dilemma. They are too large for pure manager-led allocation — the principal-agent gap with external managers becomes uncomfortable at this scale, and the relationship-management workload exceeds what a small family team can handle. They are too small for a full institutional CIO function — the cost (a senior CIO at $750k–$1.5M all-in plus a small investment team) is meaningful relative to AUM, and the volume of decisions does not justify a full-time team. The historical compromise was a single in-house investment director or a part-time advisor; the result was usually under-resourced relative to the asset complexity.

The CIO-as-a-service model has matured to fill this gap. The structure is straightforward: an experienced senior CIO, supported by a specialist team, serves three to seven family-office clients in a structured, contracted relationship. The CIO sets investment policy, manages the institutional manager roster, runs the asset-allocation framework, and presents to the family's investment committee on a defined cadence. The fees are typically fixed-plus-AUM (with a base fee and a basis-point AUM component) and run substantially below the cost of a comparable in-house function while delivering meaningfully better institutional rigor than a single internal investment director.

The model works well in three specific cases. First, when the family principal is operationally engaged in their primary business and lacks time to develop personal investment infrastructure. Second, when the family has experienced a key-person departure (the previous in-house CIO retired, or moved to a single-family situation) and needs continuity while the next generation builds capacity. Third, when the family is in transition between generations and wants institutional rigor in the wealth structure during a period of governance change.

The model fails in two specific cases. First, when the family wants the CIO to also handle direct-deal sourcing — direct deals require time and relationship investment that a fractional CIO cannot deliver, and the conflict between manager allocation and direct-deal sourcing is structural. Second, when the family principal wants the CIO function to be fully in their meeting cadence rather than the CIO's structured cadence — at that point the relationship economics break.

For mid-tier family offices considering the structural question, the CIO-as-a-service option deserves a hard look. Brilwood operates in this space with a small, deliberately-selected client cohort.