Saving
Money market funds and deposit accounts fail in different ways
Both hold short-term cash and both look safe. What happens under stress is where they separate.
Everything below about cash funds versus deposit accounts comes from what actually happens rather than from what is supposed to.
What holds up in practice
- A deposit is a debt owed to you by a bank.
- A cash fund is a holding in short-term instruments, not a deposit.
- Deposit protection schemes generally do not cover fund holdings.
What a deposit actually is
When you put money into a savings account, you are lending it to the institution, which owes you the balance plus any interest. The bank does not hold your specific money; it uses deposits to fund lending, which is the basic mechanism of banking everywhere. Your protection comes from the institution's solvency and, in most countries, from a statutory deposit protection scheme up to a limit.
The rate is set by the institution and can be changed, usually with notice for a reduction, according to local rules. The balance itself does not move with markets, which is the characteristic that makes deposits suitable for short-term needs.
What a cash fund actually is
A money market or short-term cash fund pools money and holds very short-dated instruments issued by governments, banks and large companies. You own units in that pool rather than a debt owed by a bank, which is a materially different legal position.
The arithmetic is straightforward: the return reflects what those instruments yield, less the fund's charges, and it moves as short-term rates move. In normal conditions the value per unit is stable or near stable, which is why such funds are described as cash-like. They are not deposits, and in most jurisdictions statutory deposit protection does not apply to them at all.
How each one fails
A deposit fails if the institution fails, at which point the protection scheme becomes the relevant question and the limit becomes the relevant number. A cash fund fails differently: under severe stress the instruments it holds can become hard to sell at their expected price. That can produce a small loss of value or a temporary restriction on withdrawals, both of which have occurred historically in various markets.
Practically, neither failure mode is common, but they are unrelated, which is the reason the two products are not interchangeable. The important point is that safe means different things in the two cases, and the difference only appears under stress.
Access and timing
Money in an instant-access deposit account typically reaches a current account quickly, subject to the provider's processes. Selling fund units involves a dealing cycle, and the proceeds usually arrive some days later depending on the platform and the fund.
That delay is irrelevant for money set aside for a purchase in six months and disqualifying for money that might be needed today. Anyone using a cash fund as part of a reserve should know the actual settlement time rather than assume it is immediate.
The practical test is the same as for any reserve: how long from decision to spendable money, measured rather than estimated.
Cost and tax treatment
A deposit account has no explicit charge, though the rate offered already reflects what the institution intends to keep. A fund has a stated ongoing charge deducted from returns, and a platform holding it may add its own fee on top.
For most households, the tax treatment of interest and of fund distributions differs in many countries, sometimes substantially, and can depend on the wrapper used. Comparing a deposit rate with a fund yield without accounting for charges and tax compares two numbers that are not equivalent. Rules vary by jurisdiction and change, so the current treatment where you live is the only reliable basis for any comparison.
The right answer depends on your tax situation, which this cannot see.
Choosing on the actual requirement
The requirement is usually expressible in two numbers: when the money is needed and how much certainty the balance requires. Where the answer is soon and complete, a protected deposit does the job with the least complexity. Where the sum is larger than protection limits and the horizon is months rather than days, a cash fund becomes a genuine alternative worth understanding.
Large balances are the common case for looking beyond deposits, because protection limits apply per institution rather than per amount. This is general information about how the two products work and not a recommendation to use either one.
The takeaway
A deposit is a debt owed to you; a fund is a holding you own. They behave alike until the moment they do not.
The decision is rarely about picking the best option — it is about avoiding the expensive one.
Questions readers ask
Are money market funds covered by deposit protection?
Generally not, because they are investments rather than deposits. Investor compensation schemes may apply in some jurisdictions but they cover different risks; check the rules where you live.
Why would anyone use a cash fund instead of a savings account?
Usually because the balance exceeds deposit protection limits or because the yield on short-term instruments differs from what banks are paying. Both are situational rather than general.
