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Do you know where your savings are really held?
Investment and money apps offer top instant-access and cash Isa rates
Some of the most competitive savings rates on the market – up to 5% AER – come from brands like Chip and Moneybox. But while these deals are attractive, these providers aren’t actually banks.
Many are investment or money-management apps that partner with other banks to store your cash, including big high street names such as Barclays and HSBC.
But does this matter, and is it anything to worry about? Here, Which? takes a closer look at how accounts with these providers work and explains how safe your money is.
Who's behind the top savings deals?
Some of the providers offering savings accounts today aren’t banks, but apps and platforms that offer these accounts alongside other financial services. It’s important to understand how they work — and how your money is protected.
These firms don’t offer traditional banking services such as current accounts and debit cards. Instead, savings and Isa accounts are offered alongside a wider range of financial products, including investments and even mortgages.
They’re often structured similarly to e-money institutions (EMIs) – firms authorised to hold and move money, but which don’t hold a UK banking licence. That means they must meet safeguarding requirements designed to protect customer funds.
This involves keeping your money separate from the firm’s own finances. For example, by placing deposits in a separate account with a regulated bank, holding it in low-risk investments, or protecting it through insurance or a similar guarantee.
- Find out more: best savings rates 2025
How do rates compare?
Investment or money-management app products currently dominate the instant-access savings and cash Isa market.
This table compares the best instant-access savings and cash Isa accounts. Results exclude products that impose restrictions on opening or withdrawals and are ordered by rate.
| Instant-access savings account | AER | Instant-access cash Isa | AER |
|---|---|---|---|
| Cahoot Sunny Day Saver | 5% | Moneybox Open Access Cash Isa | 5.05% |
| Sidekick OakNorth Easy Access | 4.76% | Tembo Money Cash Isa | 4.8% |
| Chip Instant Access Account | 4.6% | Monument Bank Easy Access Cash Isa | 4.76% |
| Kent Reliance Easy Access Account | 4.5% | Charter Savings Bank Easy Access Cash Isa | 4.59% |
| Saffron Building Society E-Saver Account | 4.5% | Marsden Building Society Online Cash Isa | 4.55% |
Source: Moneyfacts. Correct as of 30 April 2025, but rates are subject to change.
Investment apps Sidekick and Chip offer the second-best and third-best instant-access rates, while investment platform Moneybox and mortgage broker app Tembo Money top the instant-access cash Isa tables with their deals.
Rates are currently highest for instant-access cash Isas, which allow you to save up to £20,000 a year tax-free. If you are willing to restrict yourself to three withdrawals a year, then you could get as much as 5.71% AER with Moneybox's limited access cash Isa.
Other investment or money management apps that have been known to offer top cash Isa rates include Trading 212 and Plum. The former topped the charts last July when it launched its first instant-access cash Isa with a rate of 5.2%. Although it now offers a lower 4.35%.
Plum's first instant-access cash Isa product, which only allows three withdrawals a year, also had a market-leading rate of 5.15% when it was released in March 2025. The rate has since dropped to 5.06%.
- Find out more: best savings accounts
How safe are your savings?
These apps are authorised and regulated by the Financial Conduct Authority (FCA). They use partner banks to hold your money because FCA rules require them to keep customer cash separate from their own funds and ring-fenced, so they cannot use them whatsoever.
And because these third-party banks are covered by the Financial Services Compensation Scheme (FSCS), your savings benefit from the same protections as if you deposited your money directly into any UK bank. This means you can claim up to £85,000 for any shortfall in funds should the bank go bust.
That £85,000 is per person, per bank. So using a savings product from an investment or money app that spreads funds across multiple providers means you potentially benefit from far more FSCS-protection than if you opened a single account with an actual bank.
For example, let's say you opened an account with Tembo Money and your funds are divided between its four partner banks. You could, in theory, get up to £340,00 protection.
But a word of warning: if you already have a large sum invested in one of these partner banks separately and the app provider also puts a chunk of your savings into the same bank, you could potentially go over the £85,000 limit, and some of your money could end up unprotected.
Providers that don't have a UK banking licence would also need to make an FSCS claim on your behalf, and the process could take longer to settle than if you held an account directly with the bank. You may also be liable to pay any administrative costs.
- Find out more: Financial Services Compensation Scheme explained
Where your money is held
Moneybox spreads cash Isa funds across 10 banks, including HSBC, Santander and Barclays.
Trading 212 holds cash in Barclays, NatWest and JPMorgan.
Tembo Money partners with Barclays, Bank of Scotland, Aldermore Bank and Shawbrook Bank.
Chip and Plum, on the other hand, are 'powered by' ClearBank and Citi Bank, respectively.
Savings in wealth management app Sidekick's Easy Access pot are placed in OakNorth Bank.
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Sign up nowWhat to check before you open
If you're unsure whether the provider you are opening an account with is a bank or another type of provider, read the small print first.
The company should explain how it operates on the product website. Chip, for example, has a section which provides details on how your money is protected and a link to a fuller explanation. Moneybox also has a section about FSCS protection.
The provider's partner banks should be covered by FSCS protection. Banks sometimes merge, however, and that can have a significant impact on the protection of your savings.
Use our tool to search for a bank or building society and we'll tell you who they own, or are owned by, and how much protection you'll get under that brand.
What else should you consider?
Use our guides to finding the best savings account and best Isa account to help make a more informed decision.
From August to September 2024, we asked 4,524 members of the public to rate their bank or building society. Based on those results, we created a customer score for each savings provider.
We've also analysed thousands of savings products and given each provider an overall interest rate score, highlighting which companies offer consistently competitive rates.
Moneybox, for example, not only offers the best cash Isa rate but is also a Which? Recommended Provider and has a customer score of 83%. Cahoot, on the other hand, which currently has the top instant-access product, was the lowest-ranked provider in our analysis; it scored a less-than-impressive 61%.
Our other current WRPs are Zopa, Marcus by Goldman Sachs, and Yorkshire Building Society.
