Should you build a family office or buy a platform? Build a staffed family office when your wealth is large and complex enough to justify a seven-figure annual fixed cost and you need bespoke, full-time decision-making. Buy a platform when you primarily need consolidation, reporting and administration handled reliably — which describes most wealth owners. For many families the honest answer is a hybrid: a lean team augmented by a platform, or a platform alone from $25,000 a year.“Build vs buy” is the central decision in private wealth operations, and it is usually framed too narrowly — as salaries versus a software fee. The real comparison is between two fully-loaded operating models. This article gives a framework for making it honestly, and names the point at which each option wins.

What “build” really costs

Building means standing up and staffing your own office. The cost is the fully-loaded cost of a small, specialised business: senior compensation (with benefits and bonuses adding 30–50% over base), enterprise technology contracts, professional services, office overhead, and the principal’s own time spent hiring and overseeing it. Even a lean office rarely runs below $1 million a year, and a substantial one runs to several million. The advantage you are buying is control and bespoke capability — full-time people who know your situation intimately and can act on it.

What “buy” really costs

Buying means licensing a platform that delivers the office’s core functions — aggregation, reconciliation, consolidated reporting, document and entity management — as a service. The cost is a known annual fee that does not scale with assets under management. EtonAlpha™, for example, starts at $25,000 a year. What you trade away is full-time bespoke staff; what you gain is the same family-office-grade capability at a fraction of the cost, with the administration handled and the data consolidated automatically.

How to compare them honestly

An honest comparison requires totalling the true cost of each, not the visible one. Work through four steps:

  1. Total your fully-loaded build cost: staff compensation including benefits and bonuses, technology, professional services, overhead, and your own management time valued at a realistic rate.
  2. Define what you actually need: bespoke full-time decision-making, or reliable consolidation and administration? Be honest about which problem is real.
  3. Total the buy cost: the platform fee plus any residual professional services you still need.
  4. Model over five years, including growth: a platform fee that is flat as assets grow looks very different from staff costs that rise with complexity.

When does each option win?

Build wins when wealth is large and genuinely complex, when full-time bespoke judgement is required daily, and when the fixed cost can be spread across a balance sheet large enough to absorb it — conventionally above roughly $100–250 million. Buy wins for the large majority of wealth owners below that threshold, and for many above it who find their expensive internal systems underperform a modern platform. The hybrid — a small team running on a platform rather than spreadsheets — increasingly wins for offices that need some bespoke capability but refuse to carry a bloated back office.

The decision should be driven by complexity, not ego. A family office is a means, not a status symbol; the goal is control, clarity and good decisions, and there is now more than one way to buy them. Eton’s Family Office Cost Calculator lets you run your own numbers — assets, entities, staff and jurisdictions — and see the build cost against EtonAlpha™ side by side, so the choice rests on evidence rather than assumption.

Frequently asked questions

Q: Is it cheaper to build or buy a family office?

A: For most wealth owners, buying a platform is far cheaper. A built, staffed office rarely costs under $1 million a year fully loaded, while a platform such as EtonAlpha™ starts at $25,000. Building only wins when wealth is large and complex enough to justify the fixed cost.

Q: What is a hybrid family office model?

A: A hybrid model pairs a small in-house team with a wealth platform, so the office gets some bespoke capability without carrying a full back office. The platform handles aggregation, reconciliation and reporting; the team focuses on judgement.

Q: At what point does building a family office make sense?

A: Generally above roughly $100–250 million in assets, where the seven-figure fixed cost can be spread across a large enough balance sheet and full-time bespoke decision-making is genuinely required.