Single Family Office: What It Is, What It Costs, and When It Makes Sense
Written By: Ryan Morrison
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Most conversations about single family offices start with a number. How much do you need? What does one cost? Is $100 million enough, or do you really need $250 million before it makes sense? These are reasonable questions, but they are the wrong starting point. The more useful question is what a family office actually does that justifies its cost — and whether the structure that has kept one family's wealth intact for 157 years applies to someone building wealth for the first time.
Ilka Gregory is president and CEO of a single family office established in Brooklyn in 1866. The office now serves four main family branches, more than 80 shareholders, and seven generations — from a G4 member in her nineties to a baby born on December 31st. She is the first non-family member and the first woman to run the office, and she also leads a peer group of approximately 100 women single family office executives. Her view of what a family office is, what keeps it functional, and what it cannot do for families below a certain scale is grounded in operating reality, not theory.
TL;DR
A single family office is a private company that centralizes investment management, tax, estate, trust services, and governance for one family — and operates as a cost center with no outside clients
The meaningful threshold for a standalone single family office is typically $100M-$250M, driven by annual operating costs of $1M-$3M or more
The difference between a single family office and a multifamily office is not primarily the services — it is the governance structure and investment centralization
The secret to preserving wealth across seven generations, in Ilka's telling, is centralization: consolidated decisions, shared governance, and institutional memory that outlasts any individual
Urgency from a counterparty — "the close is end of month" — is a disqualifying signal, not a reason to accelerate diligence
First-generation wealth creators at $25M-$50M are better served by a trusted advisor at a private bank or multifamily office combined with a peer network than by building a standalone office
Table of Contents
What a single family office actually does
A single family office is a private company that centralizes investment management, tax planning, estate administration, trust services, and family governance for one bloodline. It operates as a cost center — not a profit center — with no outside clients and no revenue stream beyond the family's own capital.
That definition is accurate but incomplete. What it misses is the operational reality. "Running a family office is running a small business," Ilka said. The office she leads manages investments across four family branches, handles tax preparation and filing for select family members, serves as trustee and co-trustee on multiple trusts, and provides concierge services including bill pay and household payroll for some older family members. Her team of seven competes for talent against Goldman Sachs and institutional asset managers. Every hire is a cost the family absorbs directly.
The services a family office actually provides vary considerably across the industry. Some offices are purely investment-focused — no tax, no financial planning, no bill pay. Others outsource the investments entirely and handle everything else. The one consistent element, based on Ilka's peer group of roughly 100 single family office executives, is a strong tax function. Whether that sits in-house or is outsourced, it is almost always present.
What distinguishes the single family office model from every alternative is not any specific service. It is the alignment of incentives. Unlike a bank, an RIA, or a multifamily office, a single family office has no interest in wallet share. "We're really indifferent," Ilka said. "We want to do what's best for each family member. If they want a relationship with a traditional private bank, that's fine too."
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Single family office vs. multifamily office — the real distinction
The core difference between a single family office and a multifamily office is not the services offered — it is the governance structure and how investment decisions are made.
Ilka describes her office as "a multifamily office for one bloodline." Within a single family office, investment decisions are centralized even when individual family members hold different amounts of capital. Each branch may have distinct pools of assets based on shares of family stock, but the investment framework sits under one roof and reflects a unified strategy. At a multifamily office, by contrast, each family has its own investment advisor agreement, its own investment policy statement, and its own guidelines. Customization happens at the household level rather than the family level.
The practical implications matter for anyone evaluating which structure fits their situation. A single family office provides maximum control and alignment, but the family bears the full operational cost. A multifamily office provides meaningful personalization with shared infrastructure — and is typically more appropriate for families that want professional management without the overhead of running a standalone business. Private banks offer a third path: broad capabilities and financial stability, with less direct control than either family office model.
For most families below $100M, the multifamily office or private bank route is not a compromise. It is the more rational choice. The single family office model makes economic sense when the operational cost — often $1M-$3M annually, and averaging $3.2M according to J.P. Morgan's Global Family Office Report — represents a small enough percentage of total assets that the control premium is worth paying.
How much do you need to start a family office
There is no fixed threshold, but annual operating costs of $1M-$3M make a single family office economically viable only when those costs represent a manageable percentage of total assets — which typically means $100M-$250M or more.
Ilka pushes back on the rigidity of threshold thinking. "I don't really believe that there's one wealth threshold where it makes sense," she said. The $500M figure that circulates in the industry is not a rule. She has seen clients with several hundred million dollars who ran their family's money from a home office and did not consider themselves to have a family office at all. The question is not the number — it is the combination of complexity, desire for control, and willingness to build and run a small business.
The build-vs.-buy framework she uses is the more useful lens. Building a single family office means taking on governance, hiring, technology, compliance, and operational management in addition to investment oversight. Buying — through a multifamily office, private bank, or trusted advisor relationship — means accepting less customization in exchange for less operational burden. Neither is categorically better. The right answer depends on what the family actually wants to control and whether they have the appetite to sustain it.
For first-generation wealth creators at $25M-$50M, Ilka's advice is direct: a standalone single family office is probably not the right structure yet. Working with a trusted professional — whether at a private bank, investment bank, or multifamily office — makes sense, but only if it is someone you genuinely trust. What she sees as equally important is building a peer network. "What I do think is pretty powerful is starting to create the right community. People you trust, that you can be somewhat vulnerable with."
Managing complexity across generations without a family office?
Long Angle members with $10M-$50M in assets use the community to pressure-test decisions, compare notes on advisors and structures, and access peer intelligence that professional advisors cannot replicate. More than 850 members have committed capital through the investments platform, and the same peer layer that evaluates deals also navigates estate planning, gifting strategy, and next-gen engagement questions every week.
What keeps wealth intact across generations — the governance answer
The single most consistent factor in multigenerational wealth preservation, in Ilka's telling, is centralization. Consolidated investment decisions, shared governance structures, and institutional memory that outlasts any individual family member.
"Everything has been centralized," she said. "That's the secret sauce of maintaining wealth through seven generations." The office has been a continuous presence in the family since 1866 — not as a passive administrator but as a structural thread running through every generation's relationship with the family's wealth. Family members have grown up knowing the office exists, what it does, and how to use it. That expectation is itself a form of institutional knowledge that took over a century to build.
Governance structures are part of this continuity but they also carry their own tensions. Family charters, mission statements, and trust language codify the decisions of one generation and bind later ones. Ilka acknowledged that some of the guidelines put in place in the 1800s reflect roles and assumptions that no longer fit. "A lot of those guidelines were indicative of traditional roles that family members played back in the 1800s. The world has evolved." Changing trust language requires legal process and family consensus. Some antiquated provisions remain simply because they have always been there and no one has had reason enough to contest them.
The governance question becomes more complex as family membership grows. Ilka's office now serves four main branches and more than 80 shareholders. Spouses and stepchildren serve on the board and the investment committee — not because of bloodline but because they are committed to the mission. The pipeline question she is already thinking about: which of the current G6 and G7 members might one day be candidates for the IC or the board, and how does she begin preparing them now.
How family offices invest — and why urgency is a red flag
Family offices with established multi-generational portfolios invest on their own timeline. When a counterparty signals urgency — "the close is end of month," "this opportunity won't last" — that is a disqualifying signal, not a call to move faster.
"The minute someone says this is urgent, or we will have a close at the end of the month, that's the quickest way to get us to a no," Ilka said. The portfolio has been managed well for over 150 years. There is no shortage of deal flow. There will be another investment opportunity.
This patience is one of the structural advantages a long-established family office holds over individual investors and institutional managers with shorter horizons. Multi-generational portfolios do not have liquidity events, redemption windows, or career risk tied to short-term performance. They can simply wait.
Asset allocation inside family offices varies more than most industry commentary suggests. Some families invest directly into operating companies. Others prefer funds, accepting the K1 complexity that comes with them. Others have held public equities for generations and are sitting on concentrated, low-basis positions that are structurally difficult to trade around — a problem that has driven the growth of tax-loss harvesting strategies and direct indexing as workarounds. When the question of whether to include illiquid assets comes up, Ilka's test is whether the investment justifies the operational burden it creates. "If something illiquid makes it into the portfolio, it's because we've all come together and realized that there's real value there for the family long term."
The public markets question — why not just buy the index and stop there — gets a more nuanced answer than most family offices give publicly. Ilka's response is to question the premise. "Let's just do the public markets. Okay, but are we doing that? Are we picking stocks? Are we buying ETFs? That in itself can be a separate debate." The question is not public vs. private — it is whether any given allocation justifies the cost and complexity it introduces, whatever the asset class.
Next generation engagement and the gifting culture
Getting younger generations meaningfully connected to a family office requires meeting them where they are — not where the family office needs them to be.
Ilka just held a family meeting for G6 and G7 members. The annual shareholder meeting format — formal, programmatic, built around institutional reporting — is not the right vehicle for that audience. She is exploring a next-gen council that would help design the curriculum and agenda for a format more appropriate to younger family members. The goal is not to force engagement but to create an on-ramp that feels relevant.
Financial literacy is the practical entry point. Not discounted cash flow models, but the real decisions younger wealthy family members are likely to face: how a co-op board evaluates a buyer, what applying for a mortgage looks like when you have significant assets but limited W2 income, how to think about the first real estate purchase. "There are real life skills that school doesn't teach us," Ilka said. "You could understand a discounted cash flow model, but you may not really know what a board's going to look for when you're buying your first apartment in New York City."
The gifting culture question matters for first-generation creators as much as for established family offices. Ilka described a client she worked with at a multifamily office who discovered upon her mother's death that the family had hundreds of millions, not the $15M she had assumed. The wealth was almost entirely a concentrated stock position the grandfather had built over decades — with deep emotional attachment. The client was unprepared for the responsibility and nearly made a significant structural mistake: funding a charitable foundation with the concentrated position without understanding the restrictions the attorney general places on single-stock foundations. Working through the diversification took sustained effort.
The lesson is not just about diversification. It is about communication. Families that do not talk about money leave their heirs to discover it under the worst possible conditions — grief, legal process, and no framework for thinking about what they now own. Ilka's office counteracts this with an annual gifting cycle: letters to family members at the start of each year noting the annual exclusion amount and asking whether they want to gift to younger generations. The culture of giving is built deliberately, not assumed.
Long Angle members navigating similar questions — when to start giving, how to structure early wealth transfers, how to build a governance framework before it becomes urgent — compare notes in confidential discussions on the platform. The How to Choose a Family Office Structure post covers the structural decision in more depth.
Frequently Asked Questions
What is the difference between a single family office and a multifamily office?
A single family office manages the wealth of one family exclusively under centralized governance, while a multifamily office serves multiple unrelated families — each with separate investment agreements, investment policy statements, and guidelines — through shared infrastructure. The practical difference is control and cost: a single family office provides maximum customization and alignment but requires the family to bear the full operational expense, which can run $1M-$3M or more annually. A multifamily office shares those costs across families and typically makes more sense below the $100M threshold.
How much money do you need to start a single family office?
Most practitioners cite $100M-$250M as the practical minimum for a single family office, based on annual operating costs that can exceed $1M-$3M. The $500M figure often cited in industry discussions is not a hard rule — Ilka Gregory notes that some families with significantly less have informal family office arrangements that function effectively. Below $100M, a multifamily office or trusted advisor relationship typically delivers comparable outcomes at a fraction of the operational cost.
What does a family office CEO do?
A family office CEO manages the office as a small business — overseeing investments, tax, trust administration, governance, and family engagement — while competing for talent against institutional asset managers and banks. In a single family office, the CEO also manages the relational dynamics of serving multiple family branches with different needs, sitting in on trust distribution requests, and building the institutional continuity that makes the office useful across generations. The term used consistently across the industry for this role is "expert generalist."
What is the expert generalist role in a family office?
The expert generalist is the operating term for a family office CEO or senior leader who can navigate investment management, tax, estate planning, governance, and family dynamics without being a narrow specialist in any one domain. The role requires enough fluency across disciplines to know when to bring in outside expertise and how to evaluate it — and enough relational range to work effectively with family members across multiple generations and branches.
How do family offices approach investment decisions differently than individual investors?
Established family offices with multi-generational portfolios operate on their own timeline and treat urgency from counterparties as a red flag. "The minute someone says this is urgent, or we will have a close at the end of the month, that's the quickest way to get us to a no," Ilka Gregory said. This patience is a structural advantage — multi-generational portfolios have no redemption pressure, no career risk tied to short-term performance, and no obligation to deploy capital on anyone else's schedule. Any investment that introduces illiquidity must justify both the return potential and the operational burden — K1 complexity, reporting requirements, and staff time — before it enters the portfolio.
What should a first-generation wealth creator at $25M-$50M do instead of starting a family office?
At $25M-$50M, most practitioners — including Ilka Gregory — recommend working with a trusted professional at a private bank, multifamily office, or through a direct advisory relationship rather than building a standalone single family office. The key is genuine trust, not the institution. Alongside a professional relationship, building a peer network of others navigating similar complexity delivers decision-making value that advisors cannot replicate — access to candid, peer-sourced experience from people who have faced the same decisions without a product to sell.
Final Thoughts
The 157-year track record Ilka describes is not a product of exceptional investment returns or lucky timing. It is a product of structure — centralized decisions, shared governance, and an institutional presence that outlasted every individual who built it. That kind of continuity takes decades to establish, which is exactly why the time to think about governance, advisor relationships, and wealth transfer frameworks is before the complexity compounds, not after.
For most people reading this, a standalone single family office is not the right answer yet — and that is not a limitation, it is a data point. The more immediate question is whether you have the peer relationships and trusted advisors to pressure-test decisions that do not have obvious right answers. Building that layer now, before a liquidity event or estate situation forces the issue, is the highest-leverage thing most first-generation wealth creators can do.
The decisions Ilka describes — when to build vs. buy, how to think about governance before it becomes urgent, how to get the next generation meaningfully engaged — are exactly the questions Long Angle members work through with peers who have been there.
Long Angle is a vetted community of founders, executives, and investors navigating the same complexity. Members compare notes on advisors, structures, allocation decisions, and wealth transfer strategies in confidential peer discussions — without anyone in the room trying to sell them something. If you are managing significant wealth without the infrastructure of a family office, the peer layer may be the most useful thing you can build right now.
