Most investors spend considerable time assessing the risk of their investments — whether a stock will rise or fall, whether a bond issuer will default, whether a property market will correct. Far fewer consider the risk of the institution that holds those investments. Yet the failure of a broker, custodian, or investment platform — while rare — can be profoundly disruptive and, in the worst case, result in losses that would not have occurred had the underlying investments been performing normally.
This guide explains how client assets are — and sometimes are not — protected in the event of a platform or custodian failure, and what internationally mobile investors should do to manage this risk.
This guide provides general information about investor protection frameworks. Rules vary by jurisdiction and change over time. In the event of concerns about a specific firm, seek independent legal and financial advice immediately.
What Is Platform Risk?
Platform risk (sometimes called custodian risk or counterparty risk) is the risk that the institution safeguarding your investments becomes insolvent, misappropriates client assets, experiences an operational failure, or is subject to enforcement action that prevents normal access to your assets.
Platform risk differs from investment risk in a crucial respect: investment risk is the accepted price of seeking returns; platform risk is an operational risk that investors rightly seek to minimise. Properly structured, there is no reason why a platform failure should result in permanent loss of legitimately held client assets. However, the process of recovering assets from an insolvent custodian can be slow, expensive, and stressful — and in some circumstances, losses do occur.
The Legal Basis: Client Asset Segregation
The fundamental principle protecting investors in the event of platform failure is client asset segregation. Regulated investment firms in the UK (and equivalently in many other jurisdictions) are required to:
Segregate client assets from firm assets: Your investments are held separately from the firm's own assets and cannot be used to satisfy the firm's creditors in the event of insolvency.
Hold assets as trustee or nominee: Regulated firms hold client assets as trustee or bare nominee on the client's behalf. Legal title may be in the firm's name (or a nominee company's name), but beneficial ownership remains with the client.
Maintain a register: The firm must maintain accurate records of which client owns which assets at all times, enabling assets to be identified and returned.
When these rules are properly followed, a firm's insolvency does not affect client assets. An administrator appointed to the firm should be able to identify client assets, segregate them from the firm's own assets (which go to general creditors), and return them to clients.
The problem is when these rules are not followed. MF Global's 2011 failure illustrated this vividly: the US futures brokerage used customer funds (improperly) to fund its own trading positions. When it collapsed, there was a shortfall in client accounts that took years and significant cost to partially recover. Clients lost money they believed was segregated.
UK Regulatory Framework: FCA CASS Rules
In the UK, the FCA's Client Assets Sourcebook (CASS) sets out the detailed requirements for how firms must hold, record, and safeguard client money and client assets. Key provisions include:
Client money: Uninvested cash held with a broker must be kept in a client money bank account with an approved bank, entirely separate from the firm's own money. Client money pools are trust arrangements; the cash cannot be used by the firm.
Custody assets: Securities (shares, bonds, fund units) must be held in segregated accounts with a sub-custodian or central securities depository, identified as client assets, and maintained in an accurate register.
Reconciliation requirements: Firms must reconcile their internal records of client holdings against external custody records regularly (daily for larger firms).
CASS compliance is one of the FCA's most intensively supervised areas because the consequences of failure are so serious.
The Financial Services Compensation Scheme (FSCS)
The FSCS is the UK's investor compensation scheme of last resort. When a regulated firm fails and client assets cannot be returned in full through the insolvency process, the FSCS can compensate eligible investors.
Current FSCS limits (as of 2026):
- For protected investment business: £85,000 per eligible claimant per firm
- For protected deposits (cash at banks): £120,000 per depositor per bank (raised from £85,000 on 1 December 2025; temporary high balances are protected up to £1.4 million for six months)
These limits apply to losses that arise from a firm's failure to comply with CASS rules — not investment losses. If your platform fails and you lose money because the firm improperly mixed client and firm assets, FSCS may compensate up to £85,000 per firm.
Key limitations:
- The £85,000 investment limit covers all investment claims against a single firm, regardless of the size of the portfolio
- FSCS protection applies to FCA-authorised firms; offshore platforms may not be covered
- Losses from poor investment performance are not covered — only losses from firm failure
- Corporate entities and large institutions may have different eligibility
For investors with portfolios significantly larger than £85,000 — which describes most readers of this guide — FSCS provides a modest backstop but not meaningful protection.
How Platforms Hold Assets in Practice
Most retail investment platforms (Hargreaves Lansdown, AJ Bell, Vanguard, Interactive Investor, etc.) hold client assets through a network of nominees and sub-custodians:
Platform → Nominee company → Sub-custodian → Central Securities Depository
The nominee company is typically a wholly-owned subsidiary of the platform, holding assets on behalf of all clients. Assets are registered in the nominee's name but segregated from the platform's own assets. The sub-custodian (typically a major bank or financial institution) holds the actual securities.
This creates multiple layers between the client and the actual securities, but also multiple potential failure points. In practice, the sub-custodian layer is typically very creditworthy (major banks), and the nominee structure means securities are identifiable even if the platform fails. The risk lies primarily in operational failures — reconciliation errors, commingling — rather than sub-custodian insolvency.
Private Banks and Discretionary Managers
Private banks and discretionary investment managers typically have more direct custody arrangements. Larger private banks (HSBC Private Banking, Goldman Sachs, JPMorgan Private Bank, etc.) are themselves regulated custodians with direct access to central securities depositories. They hold assets directly in segregated accounts without an additional nominee layer.
Custody at a systemically important global bank carries very low counterparty risk — in part because the regulatory and resolution framework for G-SIBs (globally systemically important banks) makes outright failure extremely unlikely and rapid resolution more practical than for smaller firms.
However, private bank custody is not free of all risk. There have been instances of fraud at smaller private banks and wealth managers (the Madoff scandal primarily affected fund investors, but illustrated how complex custody chains can obscure misappropriation).
Offshore and International Platforms
Internationally mobile investors often hold assets through non-UK platforms — offshore investment bonds (Isle of Man, Ireland), Channel Islands-based discretionary managers, Swiss private banks, or US-based brokers. Each jurisdiction has its own investor protection framework:
Isle of Man: The Financial Services Compensation Scheme (IoM) provides up to £50,000 for investments, £50,000 for deposits, with different rules for life insurance bonds. Offshore bond platforms (often insurance company wrappers) have their own policyholder protection under Manx insurance law.
Jersey, Guernsey: Each has its own investor compensation scheme — typically £50,000 for investment business.
Switzerland: Swiss law requires strict segregation of client assets from bank assets, with strong protection under Swiss banking law. However, there is no state-backed investor compensation scheme equivalent to FSCS; protection relies on the segregation rules and Swiss custodial law.
US (Interactive Brokers, Fidelity, Schwab): The Securities Investor Protection Corporation (SIPC) provides up to $500,000 protection (including $250,000 for cash) for investment accounts. Separately, most large US brokers carry "excess SIPC" private insurance providing much higher limits.
Practical Risk Management
Diversify Custodians for Large Portfolios
The clearest practical protection is to spread assets across multiple custodians. An investor holding £5 million in investments has no meaningful FSCS protection from a single-firm failure. Distributing £1.5–2 million across 3–4 regulated custodians (each below or near a meaningful protection threshold, and more importantly each independently holding segregated assets) reduces concentration risk.
Choose custodians with different ownership structures — an independent wealth manager, a UK bank, an offshore bond wrapper — to avoid correlated failure risk.
Use Systemically Important Custodians for Core Holdings
The regulatory and resolution framework makes very large global banks unlikely to fail in a way that affects client assets. Holding core long-term assets in custody with a G-SIB (global systemically important bank) private bank carries lower custodian risk than holding with a smaller, less capitalised firm.
Verify Segregation Arrangements
Before placing assets with any platform, ask directly:
- How are my assets held — directly in segregated accounts or via a nominee?
- Who is the sub-custodian?
- What are the CASS reconciliation arrangements?
- What is your regulatory status and which compensation scheme covers my assets?
Understand Cash Sweeps and Money Market Funds
Many platforms automatically "sweep" uninvested cash into money market funds or deposit accounts. The protection applying to this cash depends on whether it is treated as client money (CASS-protected and FSCS-eligible up to limits) or as an investment in a money market fund (which is an investment, not a deposit, and FSCS covers failure of the manager, not investment performance). Clarify exactly where your uninvested cash is held.
How Global Investments Can Help
Global Investments works with internationally mobile HNW clients to ensure their assets are held in appropriate custody structures that balance administrative convenience with risk management. We can help you review your current custody arrangements, assess the regulatory protection applicable to your holdings across different jurisdictions, and recommend appropriate custodian diversification for larger portfolios. We take into account your domicile, tax structure, and the specific protections available in each jurisdiction where you hold assets.
This guide is for general information only and does not constitute financial advice or a personal recommendation. The value of investments can fall as well as rise and you may get back less than you invest. Past performance is not a guide to future returns. Tax rules, investment regulations, and the availability of specific investment vehicles change — always verify current rules and seek advice from a qualified independent financial adviser before making any investment decisions.