Family Office Banking and Treasury: Managing Institutional-Scale Personal Wealth

When a family's wealth exceeds approximately £30-50m in liquid assets, the economics and complexity of wealth management shift. The private banking model — one institution, one relationship manager, discretionary management of a pooled portfolio — starts to show its limitations. Multiple institutions, direct investment mandates, in-house treasury management, and in some cases a dedicated family office structure become the rational response.

This guide explains how families at this level approach banking, treasury management, and custodian relationships — and how the family office model manages a level of financial complexity that standard private banking cannot adequately serve.

When Private Banking Is Not Enough

The standard private banking model is designed for clients with £1-20m in investable assets. The relationship manager (RM) coordinates custody, investment management, banking, credit, and sometimes wider planning. This is efficient and works well when:

• The wealth is primarily held in financial assets (rather than operating businesses, direct property portfolios, and illiquid alternatives)
• The family has one primary jurisdiction of residence and one primary currency
• The number of entities and structures is manageable — a personal account, perhaps a trust, perhaps a company

As complexity grows — multiple jurisdictions, large property portfolios, operating companies, complex trust structures, beneficiaries in different countries — the RM model strains. The RM's network may not extend to the relevant specialists; the bank's product range may not serve all needs; the consolidated reporting becomes incomplete; and the RM changes (turnover in private banking is high), breaking continuity.

The Family Office Model

A single-family office (SFO) is a private organisation established to manage the affairs of one wealthy family. The SFO employs professionals in-house — typically a chief investment officer, finance director, legal and compliance lead, and operational staff — who coordinate the family's investments, banking, legal affairs, tax compliance, philanthropic activities, and sometimes lifestyle management.

Economic threshold: SFOs are generally established when assets reach £50-100m or more. Below this level, the cost of running an in-house team (£1-3m per annum for a lean SFO; significantly more for larger operations) cannot be justified. A multi-family office (MFO) — which provides similar services to several wealthy families, sharing the overhead — is the practical alternative for families at the £20-50m level.

What a family office does differently from private banking:

• Employs people who work solely for the family, with no product cross-sell motivation
• Selects banks and investment managers as service providers rather than deferring to them for advice
• Can hold direct investments (operating company stakes, direct property) alongside financial assets
• Maintains consolidated reporting across all assets, regardless of where they are held
• Manages the family's legal and tax affairs with internal oversight, external adviser coordination
• Coordinates succession planning, family governance, and next-generation education

Banking Relationships in a Family Office Context

A family office typically maintains multiple banking relationships rather than relying on a single private bank:

Custodian bank: the institution that holds financial assets (securities, bonds, funds) in custody. This is a purely operational function — safe keeping, settlement, corporate actions processing, reporting. The custodian bank is typically selected on the quality of its reporting systems, settlement reliability, and fee structure, rather than for its advisory capabilities. Major custodians used by family offices: BNY Mellon, State Street, Northern Trust, Pictet, DZ PRIVATBANK.

Transaction bank: handles day-to-day payments, foreign exchange, wire transfers, account management. Often a different institution from the custodian. A family office with operations across multiple jurisdictions may have transaction banking relationships with local banks in each country alongside a primary international transaction bank (HSBC, Citi, Standard Chartered provide global transaction banking to large family offices).

Credit provider: mortgage facilities, Lombard lending, aircraft or yacht finance, real estate lending. Again, often a separate relationship from the custodian or transaction bank. Private banks (Coutts, Barclays Private, JPMorgan) or specialist lenders are used here, chosen for credit appetite and terms rather than advisory capability.

Investment managers: external investment managers are engaged for specific mandates — equities, fixed income, hedge funds, private equity — rather than relying on the private bank's in-house discretionary management. The family office CIO oversees manager selection and performance.

Treasury Management

Family offices operate as institutional treasurers of their family's capital. Key treasury functions:

Cash management: maintaining sufficient liquidity for near-term expenditure (lifestyle, philanthropy, operating company needs) while investing excess cash efficiently. In 2026, overnight money market funds (institutional share classes), short-dated gilts, and bespoke notice accounts with institutions are the primary cash management instruments. Cash balances above £120,000 per institution must be diversified to avoid FSCS concentration risk.

Foreign exchange: a family with assets in multiple currencies and expenditure in multiple countries runs ongoing FX exposure. The family office treasury manages this — either passively (accept the exposure) or actively (hedge through forward contracts where the timing of a currency need is known). Specialist FX firms or the transaction bank's FX desk provide execution.

Liquidity planning: modelling cash requirements over 12-24 months and ensuring that liquid assets are matched to upcoming needs. Capital calls from private equity funds, tax payment dates, property acquisitions — all require liquidity planning.

Cash sweep and overnight investment: idle cash in current accounts earns minimal return. Family offices implement automated cash sweep arrangements — surplus cash is swept daily into a money market fund or overnight deposit — to ensure that all liquidity is working.

Custodian Selection

For a family office, custodian selection is a significant decision with long-term implications:

Reporting quality: the custodian's portfolio management reporting system is the family office's single consolidated view of financial assets. Evaluate the quality of data, frequency of updates, ability to integrate external data feeds (for assets held elsewhere), and format of reports.

Settlement reliability: particularly important for family offices that trade frequently or hold assets in multiple markets. Settlement failures are costly and time-consuming.

Fee structure: custody fees are charged as a proportion of assets under custody — typically 2-15 basis points (0.02-0.15%) per annum depending on asset size and mix. For a £50m custody relationship, annual fees range from £10,000-£75,000. Fees are negotiable for larger relationships.

Counterparty risk: the custodian holds assets under a nominee arrangement. If the custodian becomes insolvent, assets should be segregated and therefore returned to the family office (unlike a bank deposit where you are an unsecured creditor). However, the quality of segregation and the efficiency of any insolvency process depend on the custodian's jurisdiction and structure. Using a regulated, well-capitalised custodian in a strong jurisdiction reduces this risk.

Alternatives custody: private equity fund interests, hedge fund shares, direct real estate holdings, and other illiquid assets require custodians with specific capabilities. Not all bank custodians handle alternatives well.

Governance and Control

A family office requires robust governance to function effectively:

Investment policy statement: a written document setting out the family's investment objectives, risk tolerance, asset allocation guidelines, permitted asset classes, sustainability preferences, and governance over investment decisions.

Counterparty approval process: who can approve a new banking or investment management relationship; what due diligence is required before a new manager is appointed.

Authorised signatories and limits: clear documentation of who can authorise payments, at what levels, and whether dual authorisation is required above specified thresholds.

Internal audit and external oversight: periodic review by an independent adviser (or, for larger family offices, a formal internal audit function) to verify that governance is working and that financial controls are adequate.

Multi-Family Office as an Alternative

For families at the £20-50m level, a multi-family office provides similar services at lower per-family cost:

• Consolidated custody reporting across all holdings
• Investment manager selection and oversight
• FX management
• Banking relationship coordination
• Tax and legal coordination

Leading UK MFOs include Stonehage Fleming, Rathbones Family Office, Tribe Impact Capital (with a sustainability focus), and international firms including Bessemer Trust, Fiduciary Trust, and Northern Trust's family office practice.

The trade-off: an MFO shares its attention and infrastructure across multiple families, which limits the bespoke service level an SFO provides. For families with unusual complexity — a large operating business, a complex international structure, next-generation needs — the SFO may still be appropriate below the traditional asset threshold.

How Global Investments Can Help

Global Investments works with HNW and UHNW clients at the stage where their wealth management requirements are beginning to exceed what a standard private banking relationship can deliver. We help clients assess whether a family office or multi-family office structure is appropriate, evaluate custodian options, review banking relationships for efficiency and cost, and coordinate the professional advisers — legal, tax, investment management — who support a comprehensive wealth management structure.

Our international perspective is particularly relevant for families with assets and activities across multiple jurisdictions, where the coordination challenge is greatest. Contact us to discuss how your banking and investment infrastructure can be upgraded to match the scale of your wealth.