How to Start a Family Office: Legal Structure, Staffing, and Minimum AUM

$100 million in net worth is the number advisors keep coming back to as the point where a single-family office actually pencils out, because running one costs $875,000 to $6.6 million a year. That's the short answer. The longer answer is that most families who think they need a family office actually need something cheaper first.

Every year a handful of founders who just had a liquidity event ask me the same question: should I start a family office? The honest answer depends almost entirely on scale, because the legal structure is the easy part — the real cost is staffing, and staffing is where families either build something durable or badly overspend on a title.

How to Start a Family Office: The Net Worth Threshold That Actually Matters

Starting a family office means clearing a net worth threshold before it makes economic sense, not just filing paperwork. A minimum of $10 million can justify an outsourced family office relationship, $30 million is the rough floor for joining a multi-family office, and single-family offices generally only make sense above $100 million in net worth. Some advisors cite $47 million as the specific break-even point where operational efficiency starts to outweigh the overhead of building a dedicated team from scratch.

What Net Worth Level Fits Which Family Office Structure

Not every family with wealth needs to build a standalone entity. The structure that actually fits depends on where you land on the net worth spectrum, and most families overestimate which tier they belong in.

Figures are 2026 estimates blended from UBS Global Family Office Report, J.P. Morgan Global Family Office Report, Campden Wealth, and Morgan Stanley benchmarks. Cost ranges assume moderate complexity (real estate, philanthropy, and multi-generational planning); highly complex estates run higher.

The Legal Structure: LLC, SEC Exemption, and What Actually Gets Filed

Most single-family offices are formed as an LLC or corporation, wholly owned and controlled by family members. The reason that ownership detail matters so much is the SEC's family office exemption, adopted as Rule 202(a)(11)(G)-1 on June 22, 2011, which excludes qualifying family offices entirely from registration under the Investment Advisers Act of 1940. To keep the exemption, the entity must serve no clients besides "family clients," remain wholly owned and controlled by family members or family entities, and never hold itself out to the public as an investment adviser.

Families that don't cleanly fit those three conditions — most commonly because they want to manage money for a close friend, a former employee, or a charitable entity that doesn't qualify as a family client — have two paths: register under the Investment Advisers Act like a traditional RIA, or restructure as a state-chartered trust company to use the separate bank exemption. Neither path is free. RIA registration brings ongoing compliance, reporting, and custody requirements; the trust company route requires state banking supervision. Most families choose to stay inside the exemption's lines rather than take on either burden. For a deeper look at how the RIA path compares, see our family office vs. RIA breakdown.

How to Staff a Family Office Without Overbuilding

Personnel is the single largest line item in every family office budget, running 60-70% of total operating costs according to the UBS Global Family Office Report 2026. That's the number most first-time founders underestimate — they budget for the entity formation and the investment strategy, then get surprised by how expensive good people are. A core team of 2-4 professionals, typically a CEO or CIO paired with a CFO or controller, can run a family office in the $100M-$250M range while outsourcing legal, tax, and specialized investment work to outside firms.

As AUM scales past $500 million, the org chart fills in: a General Counsel, a Head of Risk, dedicated tax and real estate leads, and family governance or philanthropy staff start to make economic sense because the fee savings from bringing functions in-house outweigh the added headcount cost. Above $1 billion, staff counts of 12-25+ aren't unusual, with a full C-suite mirroring an institutional asset manager. The mistake I see most often is a family with $80 million in net worth trying to hire a full internal team before they've hit the scale where that team pays for itself — a multi-family office or an outsourced CIO almost always beats premature internal hiring at that size.

The Setup Timeline: What Actually Happens First

The mechanical steps for how to start a family office follow a fairly consistent order once the net worth threshold is cleared. Entity formation (LLC or corporation) and initial legal structuring with outside counsel typically takes 4-8 weeks. Hiring the first two or three key employees — usually a CIO or CEO first, then a CFO — runs in parallel and often takes longer than the legal work, frequently 3-6 months for the right fit given how specialized the role is. Building out custody relationships, an investment policy statement, and initial allocations across public and private markets (including SPV structures for direct deal access) generally rounds out the first 6-12 months before the office is running at full operating cadence.

One detail that trips families up: the SEC's "key employee" definition for the family office exemption requires that a person has performed investment-related functions for the family for at least 12 months before they can be treated as exempt personnel. That means the exemption isn't automatic on day one for every new hire — it's worth structuring the first year of hiring with outside counsel who understands that lookback requirement, rather than discovering the gap during an audit.

Common Mistakes Families Make When Setting Up a Family Office

The most expensive mistake is building the full team before the assets justify it. A family with $60 million who hires a CIO, CFO, and General Counsel at market rate — easily $1.2 million or more in fully-loaded compensation before any technology, compliance, or office overhead — is spending 2% of AUM on operations before a single dollar is invested, well above the 20-120 basis point range that makes a family office economically rational. That same family joining a multi-family office would likely pay 0.4%-0.7% of AUM for comparable investment access.

The second mistake is underinvesting in the investment policy statement (IPS) before hiring anyone. An IPS sets asset allocation targets, liquidity requirements, and manager selection criteria, and it should be drafted with outside counsel and an investment consultant before the first CIO is hired — not after, when a new hire's preferences end up dictating strategy instead of the family's actual goals. The third mistake is ignoring succession planning until it's urgent: Campden Wealth research consistently finds that fewer than a third of family offices have a formal, documented succession plan for both leadership and ownership, despite 70%+ of family wealth statistically failing to transfer successfully past the second generation.

Finally, families frequently underestimate the technology spend needed for reporting and consolidation across public equities, private funds, real estate, and direct deals. Even at 8% of a $1 million-plus budget, that's $80,000+ a year just on portfolio and reporting software — a cost multi-family offices absorb across dozens of families, which is another reason the $47 million-$100 million range so often favors an MFO over building alone.

Family Office vs. the Alternatives Below $100 Million

Most of the families who ask me about starting a family office don't actually need one yet. Below $47 million, an outsourced family office or a strong wealth management relationship delivers 80% of the institutional benefits — coordinated tax planning, estate structuring, and access to alternative investments — without the fixed overhead of full-time staff. Between $47 million and $100 million, joining a multi-family office spreads the same personnel costs across several families, which is why median operating costs for offices in that range run closer to $400,000 rather than the $875,000+ floor for a standalone SFO.