You generally need at least $100 million in net worth before starting a family office makes financial sense, and many advisors set the bar considerably higher — $500 million or even $1 billion for a fully staffed operation. Setup runs $500,000 to $1.5 million, and annual operating costs typically consume 1% to 3% of total net worth. Below the $100 million mark, a multi-family office usually delivers comparable services for far less.
The Net Worth Threshold
A single-family office centralizes investment management, tax planning, estate administration, and philanthropic coordination inside one private entity that serves a single family. The math only works when the family is wealthy enough that the office’s fixed costs become a small percentage of assets.
At $50 million with $1 million in annual overhead, you’re spending 2% of your wealth just to keep the lights on, before any investment fees. At $500 million, that same $1 million is 0.20%. That’s the whole logic behind the $100 million floor and why some professionals push it to $1 billion for a full-fledged office with eight or more employees.
Complexity shifts the break-even point. Families with private equity holdings, real estate across multiple countries, or operating businesses with complicated tax structures reach the point where a dedicated office pays for itself sooner than families with simpler portfolios of public securities.
What It Costs to Set One Up
Expect $500,000 to $1.5 million in one-time costs to build the legal, operational, and technological foundation. Two categories drive most of that spending.
Legal Structure
The office itself needs a legal entity. The common choices are a limited liability company, a private family trust company, or a combination of the two. An LLC forms quickly through a state secretary of state filing and provides liability protection with operational flexibility. A private family trust company takes more specialized legal work but offers greater privacy, since trust details are generally not part of the public record in most states. Many families use both: an LLC as the operating entity and one or more trusts to hold assets across generations.
Drafting the operating agreements, governance charters, and investment policy statements requires attorneys experienced in ultra-high-net-worth structures, and their fees typically account for the largest share of setup costs. Employment contracts, confidentiality agreements, and succession protocols should be in place from day one.
Technology and Cybersecurity
Portfolio management software, accounting platforms, and secure document storage require upfront licensing and installation. Family offices handle extraordinarily sensitive data — account numbers, tax returns, trust documents, personal information for multiple family members — so cybersecurity is a non-negotiable line item from the start. Standard spending covers firewalls, encrypted communications, multi-factor authentication, and ongoing vulnerability monitoring.
Annual Operating Expenses
Once running, a fully staffed office typically costs 1% to 3% of total net worth per year. For a family with $200 million, that’s $2 million to $6 million annually. Benchmarking studies suggest internal operating costs alone average roughly 0.40% to 0.55% of assets under management for offices in the $200 million to $500 million range, with the percentage declining as the office grows. The higher end of the 1% to 3% range reflects all-in costs, including external investment manager fees, fund expenses, and transaction costs layered on top of internal overhead.
Staff Compensation
Personnel is the largest recurring expense by a wide margin. A chief investment officer, responsible for portfolio strategy, manager selection, and market monitoring, commands compensation that varies with the office’s size and investment complexity; total packages including salary and bonuses commonly reach seven figures at larger offices. Beyond the CIO, most offices employ or retain tax specialists, accountants, an estate planning attorney, and administrative staff. Smaller offices outsource some of these roles to keep headcount low; larger ones build fully internal teams.
Audit, Compliance, and Legal Fees
Annual auditing and regulatory filing costs add $50,000 to $150,000 or more depending on the complexity of the asset structure, covering independent financial audits, tax returns for multiple entities, and any required regulatory filings. Ongoing outside legal counsel is also needed to update trust documents, review contracts, and respond to changes in tax law.
Insurance
A comprehensive insurance program covers directors and officers liability, errors and omissions, and cyber liability. For a single-family office managing $100 million to $500 million with 5 to 15 staff, premiums generally fall in the $40,000 to $85,000 range annually. Smaller offices with fewer employees and lower assets under management may pay $15,000 to $40,000. Investment activities, staff size, and claims history all move the number.
The Tax Question That Changes the Real Cost
Whether your family office can deduct its operating expenses — salaries, rent, technology, professional fees — depends on whether the IRS considers it a “trade or business” rather than a personal investment activity. Federal tax law allows deductions for ordinary and necessary expenses paid in carrying on a trade or business, including reasonable compensation, travel expenses, and rent for business property.1Office of the Law Revision Counsel. 26 USC 162 – Trade or Business Expenses
The statute doesn’t precisely define “trade or business.” Courts have interpreted it as an activity conducted with continuity and regularity, with a primary purpose of earning income or profit. For a family office, the practical question is whether the office provides genuine advisory services to family members, comparable to what an outside investment firm would provide, or simply manages the family’s own passive investments.
In Lender Management, the Tax Court found that a family office qualified as a trade or business because it provided investment management and financial planning services to family members comparable to those of a hedge fund manager. Critical factors included compensation through a profits interest structure, the ability of family members to withdraw their money, and geographically dispersed family members with distinct financial needs requiring tailored advice. Families that want to maximize deductibility should structure the office with these principles in mind: documented service agreements, arm’s-length fee arrangements, and evidence that the office functions like a professional advisory firm.
If the office doesn’t qualify as a trade or business, its operating expenses may be treated as personal investment expenses, which face significant limitations under current tax law. Getting this right at setup can save hundreds of thousands of dollars a year, which makes it one of the most consequential decisions in the launch process.
A Note on SEC Registration
A family office that only serves its own family does not need to register with the Securities and Exchange Commission as an investment adviser. Federal law excludes “any family office, as defined by rule” from the definition of an investment adviser.2Office of the Law Revision Counsel. 15 USC 80b-2 – Definitions To qualify, the office must have no clients other than family clients, be wholly owned by family clients and controlled by family members or family entities, and not hold itself out to the public as an investment adviser.3eCFR. 17 CFR 275.202(a)(11)(G)-1 – Family Offices Opening the office to outside investors breaks the exclusion and pulls the office into full SEC registration with ongoing compliance costs, so build that boundary into the governance documents from the start.
If You’re Below the Threshold: The Multi-Family Office
Most families with less than $100 million in net worth are better served by a multi-family office. An MFO serves several wealthy families through a shared team, spreading staff, technology, and infrastructure costs across multiple clients. Most MFOs work with families that have at least $30 million.
Instead of paying millions in annual overhead, MFO clients typically pay a percentage of assets under management. Fees generally run 0.50% to 2.00%, depending on portfolio size, service complexity, and the specific firm. A family with $50 million paying 0.75% would spend $375,000 per year, a fraction of what a dedicated single-family office costs. Some MFOs also layer performance-based fees on top of the base management fee.
MFOs are registered investment advisers, which means they file Form ADV with the SEC and are subject to regulatory oversight that single-family offices avoid.4SEC.gov. Form ADV – General Instructions From the client’s side, that registration gives you a way to review the firm’s disclosures, conflicts of interest, and disciplinary history through the SEC’s public database before signing on.
The trade-off is control. In a single-family office, you dictate the investment mandate, hire and fire staff, and set every policy. In an MFO, you’re one of several clients, and the firm balances your preferences against its broader operations. For families whose financial complexity doesn’t justify the cost of a standalone office, an MFO delivers institutional-quality resources — estate planning, tax optimization, philanthropic coordination, access to alternative investments — at a manageable cost.