The Six-Month Private Office: Renting Institutional Wealth Management Without the Permanent Payroll

There is a peculiar moment in the financial life of many successful Britons: the point at which their affairs have grown too intricate for the family accountant, yet not quite substantial enough to justify hiring a private secretary, a tax director and an investment committee. The wealth sits awkwardly between two worlds — too complex for the high street, too modest for the marble.

Into this gap has stepped a quietly expanding proposition: the fractional family office. Rather than retaining a full private office at an annual cost that can comfortably exceed £500,000, clients engage the same disciplines — consolidated reporting, tax coordination, succession planning, investment oversight — for a defined number of days per quarter, a fixed project, or a six-month engagement. Call it the advisory board in your pocket.

Why the Model Has Arrived Now

The timing is not accidental. A generation of entrepreneurs who sold businesses through the 2010s, along with professionals accumulating seven-figure portfolios across ISAs, pensions and property, now face genuinely multi-disciplinary problems: capital gains on carried interest, non-dom rule changes reshaping residence planning, pension allowances squeezed by successive chancellors, and children scattered across jurisdictions.

No single adviser owns all of that. Traditionally, the answer was to assemble one — at considerable expense. The fractional model argues that most families need the full assembly only in bursts: around a liquidity event, a relocation, a divorce, or an inheritance. Between those peaks, a lighter structure suffices.

Several London-based multi-family offices now sell their services on a days-per-year basis rather than a percentage of assets, and a handful of ex-private-bankers have set up standalone practices offering precisely this — a virtual investment committee, a tax specialist on retainer for twenty days a year, an estate planner engaged only when the will needs redrafting. The pitch is seductive: institutional rigour, without the payroll.

The Arithmetic of Engagement

A traditional family office for a £20 million estate might cost 0.5–1% of assets annually once salaries, systems and overheads are counted. A fractional arrangement typically prices in one of three ways:

• Day rates: £2,000–£5,000 per day for senior figures, with perhaps 30–60 days purchased annually — call it £100,000 to £250,000 in a busy year.
• Fixed project fees: £25,000–£75,000 for a defined piece of work, such as restructuring a property portfolio or designing a succession plan.
• Hybrid retainers: a modest base fee plus project charges, sometimes with a capped all-in figure.

For portfolios between £5 million and £30 million, the fractional route frequently costs a third to a half of the full-time equivalent. Below £5 million, even the fractional model is often overkill — a good private client accountant and a fee-based adviser will do. Above £50 million, the case for a dedicated office becomes harder to resist, if only for confidentiality and speed.

Where the Conflicts Hide

The model is not without its soft spots, and discerning clients should interrogate three in particular.

First, the bundled product question. Some fractional providers are, in truth, asset managers in disguise, using the advisory relationship as a funnel into discretionary mandates carrying 1% or more in annual fees. If your six-month private office keeps steering conversation towards products it happens to administer, the day rate is not the real price.

Second, the continuity gap. A part-time team sees your affairs in snapshots. Transactions move quickly, HMRC does not, and a tax position reviewed in March may be stale by September. Ask explicitly who monitors the estate between engagements, and what triggers an unscheduled call.

Third, the independence illusion. A fractional adviser serving a dozen families simultaneously faces the same cross-client tensions as any multi-family office — allocation of opportunities, priority of attention, quiet asymmetries of information. Few disclose this unprompted.

A Practical Test Before You Sign

Before engaging any provider, ask for three things in writing: a fee schedule showing every revenue stream, including any received from third parties; a named individual responsible for your file between engagements; and a conflicts policy that means something more than a paragraph of boilerplate.

Then run a pilot. Six months, one defined project — consolidating your reporting, or stress-testing your estate plan against the current inheritance tax regime. Judge the provider not on charm but on documentation: did they leave your affairs more legible than they found them?

The Verdict for the In-Between Wealthy

For British clients whose wealth has outgrown the accountant but not yet earned the payroll, the fractional family office is a genuinely useful instrument — provided it is bought with the same scepticism one would apply to any other purchase of six figures. The machinery of serious wealth management is now available by the day. The judgment to use it well remains, as ever, a full-time occupation.