Pensions & Retirement

Money Market Funds Guide UK — Low-Risk Investing Explained

How money market funds work in the UK, typical returns, risks, tax treatment, and how they compare to savings accounts, cash ISAs, and other low-risk options.

Money market funds are a popular way to earn interest on cash while keeping risk extremely low. Here’s how they work.

What Is a Money Market Fund?

Feature Detail
Definition Investment fund holding very short-term, low-risk debt
What it holds Treasury bills, certificates of deposit, commercial paper, short-term bonds
Goal Return close to the Bank of England base rate with high stability
Risk level Very low — but not FSCS protected
Access Same day or next day in most cases
Minimum investment Typically £1–£100 on platforms
Typical yield 4.0–4.5% (gross, in a 4.5% base rate environment)

How They Work

Step Detail
1 You invest money into the fund (via a platform or broker)
2 The fund manager pools money from all investors
3 Invests in short-term, high-quality debt instruments
4 Interest earned is passed to you as distributions (income units) or reinvested (accumulation units)
5 You can withdraw at any time (same day or T+1)
Fund OCF Yield (approx.) Min investment
Royal London Short Term Money Market 0.10% ~4.3% £1 (via platform)
L&G Cash Trust 0.11% ~4.2% £1
Vanguard Sterling Short-Term Money Market 0.12% ~4.3% £100
Aberdeen Standard Liquidity Fund 0.10% ~4.3% £1
BlackRock ICS Sterling Liquidity 0.10% ~4.3% £1
Fidelity Cash Fund 0.15% ~4.1% £1
HSBC Sterling Liquidity 0.10% ~4.2% £1

Yields are illustrative and fluctuate with interest rates. OCF = Ongoing Charges Figure.

Money Market Funds vs Savings Accounts

Factor Money market fund Easy-access savings account
Typical return 4.0–4.5% 3.5–5.0% (best rates)
FSCS protection No Yes (up to £85,000)
Access Same day / T+1 Instant
Risk Very low (but not zero) Zero (within FSCS limit)
Can hold in ISA Yes Yes (Cash ISA)
Can hold in SIPP Yes No (most SIPPs don’t offer deposit accounts)
Platform fee 0.1–0.45% of your balance None
Rate changes Tracks base rate closely Bank can (and does) change rate without notice
Switching Instant on same platform May need to open a new account

When Money Market Funds Make Sense

Situation Why
Cash within an investment platform Earn interest on uninvested cash alongside your stocks and shares ISA/SIPP
Emergency fund within an ISA Keeps the ISA tax wrapper while earning near-base-rate returns
Large sums over £85,000 Savings accounts are only FSCS-protected up to £85k — MMFs diversify across many institutions
Parking cash before investing While you decide what to invest in
Corporate treasury management Businesses parking cash reserves

When a Savings Account Is Better

Situation Why
You want FSCS protection Bank deposits are protected up to £85k
Small amounts (under £85k) Savings account is simpler and protected
Not using an investment platform Saves on platform fees
You want the best headline rate Top savings accounts can beat MMFs by 0.2–0.5%
You want zero risk MMFs can theoretically lose value (though extremely unlikely)

Tax Treatment

Tax situation Treatment
Outside ISA/SIPP Taxed as savings interest at your marginal rate
Personal Savings Allowance £1,000 (basic rate) / £500 (higher rate) / £0 (additional rate)
In a Cash or Stocks & Shares ISA Tax-free
In a SIPP Tax-free (taxed on withdrawal as pension income)
Accumulation units Income is still taxable in the year it’s earned (even though you don’t receive cash)
Capital gains Generally none — fund value stays stable

Risks

Risk Likelihood Detail
No FSCS protection N/A If the fund collapsed, you could lose money
Fund value falls Extremely rare Sterling MMFs have never “broken the buck”
Interest rate falls Possible Returns drop when base rate falls
Counterparty risk Very low Risk that an issuer defaults on their debt
Platform risk Very low If your platform goes bust, your assets are ring-fenced
Inflation risk Moderate Returns may not beat inflation

How to Invest

Step Detail
1 Open an account with an investment platform (Vanguard, Hargreaves Lansdown, AJ Bell, Interactive Investor, etc.)
2 Choose your account type (ISA, SIPP, or general investment account)
3 Search for the money market fund by name
4 Invest your chosen amount
5 Distributions are paid or reinvested automatically