---
title: "Single-Family Office (SFO) | Altss Glossary"
description: "A single-family office (SFO) is a private organisation owned and controlled by one family that manages that family's investments and related financial…"
canonical: "https://altss.com/glossary/single-family-office"
---

Glossary · Allocator type

# Single-Family Office (SFO)

Also called: single family office

A single-family office (SFO) is a private organisation owned and controlled by one family that manages that family's investments and related financial affairs and has no outside clients.

Publisher: Altss LLC Published 2025-12-24 Content modified 2026-10-02

ALTSS-ALLOC-020

An SFO works for one family only. The family funds it, family members or a family board direct it, and it invests the family's capital directly or through funds. Because it serves no outsiders, a US SFO that meets the SEC Family Office Rule is not an investment adviser under the Advisers Act, so who counts as "family", who owns the office and whom it advises are the facts that matter.

## What makes an office single-family

In market usage an SFO has three features: it serves one family (often several generations and branches descended from the wealth creator), the family owns and controls it, and it takes no outside clients. It may be a standalone management company owned by family trusts, or an embedded team inside the family's operating or holding company. Staff are employees of the office; senior investment staff often co-invest alongside the family or receive a share of profits.

An SFO is an asset owner: its decisions commit the family's own capital. That distinguishes it from a [multi-family office](https://altss.com/glossary/multi-family-office) (MFO), which manages capital for unrelated clients.

## The US legal test in detail

Under the SEC [Family Office Rule](https://altss.com/glossary/family-office-rule), an office is not an investment adviser if it has no clients other than family clients, is wholly owned by family clients and exclusively controlled by family members or family entities, and does not hold itself out to the public as an adviser. The rule's definitions decide who is inside:

- **Family members** are all lineal descendants of a common ancestor, including by adoption, stepchildren, foster children and individuals who were minors when a family member became their legal guardian, plus their spouses or spousal equivalents. The common ancestor may be living or dead but must be no more than 10 generations removed from the youngest generation.
- **Former family members** are spouses, spousal equivalents or stepchildren who left the family through divorce or a similar event.
- **Key employees** are executive officers, directors, trustees, general partners and similar, plus employees (other than clerical or administrative staff) who take part in the office's investment activities and have done so, there or in a similar role elsewhere, for at least 12 months. They and certain of their spouses can be family clients.
- **Family entities and other family clients** include qualifying trusts and estates, charitable organisations funded exclusively by family clients, and companies wholly owned by and operated for the sole benefit of family clients.
- **Control** means the power to exercise a controlling influence over management or policies, other than solely as an officer.

If a person who is not a family client becomes a client through the death of, or another involuntary transfer from, a family member or key employee, that person is treated as a family client for one year after the transfer of legal title is completed, giving the office time to restructure.

## Investor status

An SFO that meets the rule, manages more than $5 million, was not formed to make the investment, and has its investment directed by a person with the knowledge and experience to evaluate it is an [accredited investor](https://altss.com/glossary/accredited-investor) under Rule 501(a)(12). Its family clients are accredited under Rule 501(a)(13) when it directs their investment. For [qualified purchaser](https://altss.com/glossary/qualified-purchaser) status the test applies to the investing vehicle: a company owning at least $5 million in investments that is owned by related family members (or their estates, or foundations, charities or trusts set up for them) qualifies, as does any person that owns and invests on a discretionary basis at least $25 million in investments (Investment Company Act section 2(a)(51)(A)(ii), (iv)).

## How SFOs allocate

Governance ranges from principal-led, where the wealth creator decides, to a professional CIO with an investment committee that includes family members and outsiders. The principal, usually the wealth creator or head of the family, and the office are different actors: an introduction to one is not a decision by the other. Mandates usually reflect the source of wealth (sector knowledge, an operating company that needs capital or diversification), the family's tax position and its liquidity needs. With no external clients and no redemptions, an SFO can hold concentrated or long-dated positions that a commingled fund could not, but succession, disputes between branches or a liquidity event in the family business can change its programme quickly. Reporting usually consolidates holdings across many family entities.

## Not the same as

- [Multi-Family Office (MFO)](https://altss.com/glossary/multi-family-office): An MFO serves unrelated families, so it cannot rely on the Family Office Rule and is regulated as an investment adviser unless an exemption applies; it may act only as an adviser. An SFO serves one family and invests its own capital.
- [SEC Family Office Rule (Rule 202(a)(11)(G)-1)](https://altss.com/glossary/family-office-rule): SFO is a market description of an organisation; the Family Office Rule is the legal test for excluding it from the Advisers Act, and some SFOs do not meet it.

## How it is classified

- Classify as an SFO when the office serves only one family's members and entities and is family-owned and family-controlled.
- If the office files Form ADV as a registered adviser serving several families, classify it as a multi-family office.
- For an embedded office, record the office function and the operating company as related but separate entities, and record the investing vehicles as LPs.

## Common mistakes

- Assuming any office calling itself an SFO is outside the Advisers Act. One outside client, an owner who is not a family client, control by anyone other than family members or family entities, or holding itself out to the public takes it outside the rule, apart from the rule's narrow grandfathering of certain advice relationships that began before 1 January 2010.
- Assuming key employees cannot invest with the family. Under the rule's conditions they can be family clients.
- Treating the principal and the SFO as one investor, or the SFO and the family's operating company as one entity.
- Using AUM or cheque-size ranges for SFOs that have no dated primary source.

## Edge cases

- Several branches of one extended family can be served by one SFO if all members descend from a common ancestor within 10 generations of the youngest generation.
- A death or other involuntary transfer from a family member or key employee that makes someone who is not a family client a client starts the one-year period, not an immediate loss of the exclusion. A spouse who leaves the family through divorce becomes a former family member, who remains a family client.
- An SFO that admits unrelated families falls outside the rule and becomes, in substance, a multi-family office; if it advises on securities as a business for compensation it is an investment adviser and must register unless an exemption applies.

## Questions

### Can a single-family office manage money for friends or outside investors?

Not if it wants to stay within the SEC Family Office Rule. Advising anyone who is not a family client, other than during the one-year period after an involuntary transfer or under the rule's narrow grandfathering of certain advice relationships that began before 1 January 2010, takes it outside the exclusion.

### Who counts as family under the SEC rule?

Family members are the lineal descendants of a common ancestor no more than 10 generations removed from the youngest generation (including by adoption, stepchildren, foster children and certain former minor wards), and their spouses or spousal equivalents. Former family members, key employees and certain family trusts, estates, charities and companies are not family members, but they are family clients that the office may serve.

## Sources

1. [17 CFR 275.202(a)(11)(G)-1 - Family offices](https://www.law.cornell.edu/cfr/text/17/275.202(a)(11)(G)-1). U.S. Securities and Exchange Commission (CFR text via eCFR; LII mirror), eCFR current as of 2026-09-29; adopted 2011 (76 FR 37994), amended 2016 (81 FR 60457). Status: in force (checked 2026-10-01). 17 CFR 275.202(a)(11)(G)-1(a), (b)(1)-(3), (d)(2), (d)(4), (d)(5), (d)(6), (d)(7), (d)(8) — supports: Exclusion conditions, involuntary-transfer one-year rule, control, family client list, family entity, 10-generation family member definition, former family member, key employee 12-month test
2. [17 CFR 230.501 - Definitions and terms used in Regulation D (accredited investor)](https://www.law.cornell.edu/cfr/text/17/230.501). U.S. Securities and Exchange Commission (CFR text via eCFR; LII mirror), eCFR current as of 2026-09-29; last amended 2025-02-18 (technical, 90 FR 9684); last substantive amendment effective 2020-12-08 (85 FR 64234). Status: in force (checked 2026-10-01). 17 CFR 230.501(a)(12)(i)-(iii), (a)(13) — supports: Family office and family client accredited investor categories
3. [15 U.S.C. 80a-2 - Definitions (Investment Company Act sec. 2, incl. 2(a)(48) BDC and 2(a)(51) qualified purchaser)](https://www.law.cornell.edu/uscode/text/15/80a-2). U.S. Congress (United States Code; LII mirror), Current US Code text as published by LII (accessed 2026-10-01). Status: in force (checked 2026-10-01). Investment Company Act sec. 2(a)(51)(A)(ii), (iv) — supports: Qualified purchaser tests for family companies and discretionary investors
4. [15 U.S.C. 80b-2 - Definitions (Advisers Act s.202)](https://www.law.cornell.edu/uscode/text/15/80b-2). U.S. Congress (US Code via LII), Current US Code text as published by LII (accessed 2026-10-01). Status: in force (checked 2026-10-01). Advisers Act sec. 202(a)(11) — supports: Investment adviser definition
5. [15 U.S.C. 80b-3 - Registration of investment advisers (Advisers Act sec. 203, incl. 203(l) and 203(m))](https://www.law.cornell.edu/uscode/text/15/80b-3). U.S. Congress (United States Code; LII mirror), Current US Code text as published by LII (accessed 2026-10-01). Status: in force (checked 2026-10-01). Advisers Act sec. 203(a) — supports: Registration requirement, subject to exemptions

## Related terms

8 terms

- [SEC Family Office Rule (Rule 202(a)(11)(G)-1)](https://altss.com/glossary/family-office-rule)
- [Multi-Family Office (MFO)](https://altss.com/glossary/multi-family-office)
- [Family Governance](https://altss.com/glossary/family-governance)
- [Accredited Investor](https://altss.com/glossary/accredited-investor)
- [Qualified Purchaser (QP)](https://altss.com/glossary/qualified-purchaser)
- [Direct Investment](https://altss.com/glossary/direct-investment)
- [Co-Investment](https://altss.com/glossary/co-investment)
- [Family Office](https://altss.com/glossary/family-office)

## Concept record

Concept ID

ALTSS-ALLOC-020

Classification

Allocator type

Topics

Family offices

Version

2.0.0

Last reviewed

2026-10-02

Structured data

[JSON](https://altss.com/reference/concepts/single-family-office.json)

Source check

Legal statements checked against the cited primary sources on 2026-10-02 ([how](https://altss.com/methodology)). General information, not advice.

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