Should You Build a Family Office Under $100m?

When founders get serious about their money, usually after a sale, a lot of them start pricing up a family office. Their own investment manager, an accountant, someone to run the admin, the software, maybe a dedicated CFO. Then they see the number. A small in-house team runs $700k to $1m a year before anyone has invested a penny, and on $30m, that is more than 3% of everything you own, gone every year.

For most founders under $100m, building that team is the wrong move. The good news is you don't need it. Almost all of the work can be bought from outside for a fraction of the cost. The part you can't buy is understanding your own money well enough to tell whether the people you've hired are doing a good job.

A family office starts with structure

Start with the part nobody finds interesting: the structure. Not the investments, the thing underneath them. Which company or trust holds what, in which country, taxed how, and who it passes to. Most founders assume a family office is mostly about picking investments. It isn't. Get the structure right and every decision after it has somewhere clean to sit. Get it wrong, and you spend years and real money unpicking it, or you quietly pay for the mistake for the rest of your life.

This is the one piece worth paying a proper firm for: a serious law or tax practice that signs off on its own advice and carries the liability if it's wrong. That liability is the point. You are not buying a document, you are buying someone whose name is on the structure when the tax authority asks. It is also the piece founders skimp on to save a fee. Don't. Structure first, then the investments sit on top of it.

Building it in-house rarely adds up

Look at what a full in-house team costs. The biggest line is salaries. A family office CEO in the UK typically earns £198,000 to £264,000 a year, on the 2025 KPMG and Agreus benchmark, and that's before you've hired anyone to do the investing. Add a director, admin and the technology, and you are at $700k to $1m a year. UBS's 2026 report puts staff at 60%-70% of an office's running costs, so this is mostly a payroll decision. On $50m, that team eats 2% of your wealth a year. On $20m, 5%. The maths only starts to work somewhere past $100m.

So most families don't build it. They buy the same functions from outside, and it costs a fraction. A multi-family office charges roughly 0.5% to 1% of AUM a year, around $250k to $500k on $50m, and that covers investment management, reporting, and admin. An outsourced investment office (OCIO) can charge as little as 5 to 20 basis points on top of the underlying funds. About 80% of family offices already outsource at least part of their investing, according to J.P. Morgan's 2026 report, and only about a quarter cite cost as the reason. The real reason is talent. A family running $30m can't pay an investment manager what a hedge fund pays them, so it hires one by the slice instead.

How much of the investing you keep for yourself is a choice, not all-or-nothing. At one end, a planner or an outsourced CIO builds a sensible portfolio, and you review it a few times a year. At the other end, you make your own calls, which means knowing why you own each thing and whether you're buying in public markets or private deals, because those require different skills and different people. There is no correct answer, only an honest one about how involved you want to be.

These setups have names. A coordinated adviser network keeps a few trusted advisers with one person tying them together. Go a step further, and a virtual family office buys the work from outside providers, with software pulling it into a single view. The most built-out option, a lean single-family office, puts one or two people in-house and buys in the rest. I've laid out what each costs and who it suits in the three operating models for running a family office under $100m.

Paying for it isn't the same as getting it right

Here is the part founders get wrong. They treat investing, tax and structure as someone else's job, hand it over, and assume a good professional will take care of it. Plenty do. The problem is you usually can't tell a good job from a mediocre one until much later, when the bill arrives, or the return doesn't. You can't judge work you don't understand, and a lot of the cost of getting this wrong stays invisible until it isn't.

Becoming a professional isn't the bar. What you need are the basics: how decisions are made, what a good answer to a question looks like, and where your money sits. Once you have that, you can hand the work to someone and still know whether they're doing it well.

You already know this from running your own company. Hand a business with no systems and no numbers to a new manager, and they'll probably fail, and you won't know why until it's too late. You bring in a manager once the thing runs on systems you understand. Money is the same. Learn how it works, set up the systems and the checks, then hand over the day-to-day and keep an eye on it. Get that order wrong and nothing else you do will save it.

One person you keep close

If you outsource the work, keep one person close: whoever runs the whole thing. Call them a coordinator, or a general manager for your money. They sit across the advisers, the managers and the lawyers and make sure it holds together. Part-time or full-time, depending on how much there is to run. Someone you genuinely trust, who thinks like an owner rather than a clerk. Ideally with some skin in the game, a small equity slice or a share of the performance, so they do well when you do. That is now standard practice: family offices increasingly tie key staff in through profit-sharing and co-investments, for exactly that reason.

One mistake founders make more than any other is hiring a friend, someone they happen to know, or a relative who needs a job. Don't. Hire a professional. Interview properly, take references, and judge on character and competence, the same bar you'd set for a senior hire in your business. The same goes for the wider advisory team around them. Because that is what this is.

Run it like a business you own

There is a fair argument for keeping more in-house. Hand your structure and your data to outside firms, and you're trusting other people with sensitive things. A lean setup runs on a web of providers, and every one is a way in. Decisions slow down when nobody owns them.

But the real risk isn't outsourcing the work. It's outsourcing the understanding, paying other people to think so you don't have to. That isn't running a lean operation. It's avoidance, and it's how capable founders end up unable to explain what they own.

One concrete thing before you sign with anyone: ask exactly what the fee includes and what sits on top of it. An outsourced CIO or multi-family office fee usually stacks on top of the underlying funds' charges, and providers aren't always required to show you the full amount. If they can't give you a clear all-in figure, that tells you something.

So treat your money like a business you own. Learn enough to judge it, get the structure right, set up simple checks, hand the day-to-day to one person you trust, and keep watching. Start small and keep it lean. None of this needs a big setup. It needs you to know your own money well enough to tell whether the people you pay are doing right by it.

From where I sit

I work in wealth management, and the thing I notice from the inside is how quickly founders go quiet once they've hired someone.

The pitch lands, the mandate gets signed, and the founder relaxes. It's understandable. After years where every decision was theirs, handing the money to professionals feels like permission to stop thinking about it. But the firm they hired is a business too. Fees get reviewed. Good people leave. Sometimes the firm itself gets bought, the way Stonehage Fleming was this month. The relationship a founder thought they'd locked in for ten years quietly becomes something else, and the ones who went quiet are the last to notice.

The ones who come out of this well stay close enough to judge the firm they hired. They can still read their own statements, still ask the question that makes an adviser sit up, still tell a real answer from a comfortable one. They hand over the work and keep the judgment.

That's the whole point of this week's piece, and it's the part I'd push hardest if you were across the table from me. Hire the help. Just don't go quiet.

On the Radar

Fractional CFOs and CIOs are becoming the first hire, not the whole team.

Family offices are moving from full-time staff to hiring by the slice, often on a build-operate-transfer basis: a part-time CFO or CIO sets the structure up, and a full-time hire comes only once there's enough to justify it. For a $5M–$100M founder, it means you no longer have to choose between an expensive in-house team and nothing at all. You buy senior help by the day, get the thing built, and keep what earns its place. Read more →

Renting an investment office has gone mainstream.

About one in ten family offices now use an outsourced chief investment officer, and more than half of the assets surveyed are run with or by external managers, on Citi's 2024 survey. The reason is talent, not cost: a family can't pay an in-house investor what a hedge fund pays them. Below the size that justifies a full team, an outsourced CIO buys institutional process without the payroll. The thing to hold onto is what stays yours: which decisions you keep, and whether the manager's incentives line up with yours. Read more →

Bookkeeping is the next job to be automated away.

AI-native accounting platforms now handle multi-entity bookkeeping, bill pay and the monthly close in one place, cutting the close from weeks to days and taking out a chunk of the manual work. Bookkeeping was always the easy thing to outsource: too dull to do in-house, too costly to staff. Now software does it, which removes the decision rather than moving it. The line between what you keep and what you hand out keeps shifting, and bookkeeping has crossed it. Read more →

Going lean widens the attack surface.

The flip side of buying capability rather than building it: as offices outsource accounting, reporting, and admin, those outside firms become the way in. Cybersecurity is now one of the most outsourced jobs and one of the things family offices worry about most, according to J.P. Morgan's 2026 survey, and a lean office's web of vendors only widens exposure. Worth asking any provider plainly: where does my data sit, who can see it, and what happens to it if we part ways? Read more →

When the firm you outsourced to gets bought.

Consolidation among multi-family offices has reached the UK: Corient, the US manager, completed its purchase of Stonehage Fleming and Stanhope Capital on 1 June, creating a group with more than $500bn in assets. The firm that many families relied on has changed hands. Outsourcing isn't set-and-forget: the people, the terms and the service can all change when a provider is bought. Worth keeping your switching costs low, and not running everything through one firm you'd struggle to leave. Read more →

New on the Site

A recent piece looked at the other side of this: the decision to take money off the table in the first place, and why selling a slice of what you built isn't the same as losing faith in it. That frees up the cash. This week is about what to do with it once it's free, without having to build an empire to manage it.

Read it: Taking Money Off the Table Doesn't Mean You've Stopped Believing