In short: UK businesses in 2026 have two meaningful routes for idle cash: FSCS-protected deposit platforms and direct savings accounts (where business rates have been sitting around 4.3% as of June 2026), or money market fund products from fintechs such as Wise, Revolut, Airwallex, and Round (variable MMF yields, asset-protected but not FSCS-covered on the fund side). The right answer depends on how much you hold, how often it needs to move, and how much time you want to spend managing it.
How to think about idle business cash
Before you compare rates, it helps to understand the two structural routes and what you are actually trading.
Route 1: Deposit accounts and deposit platforms
You put money into a bank savings account or use a platform such as Flagstone, Insignis, or Akoni that spreads deposits across multiple FCA-regulated banks. Each bank deposit is eligible for FSCS protection up to £120,000 per banking group, so spreading across many banks extends that coverage to larger balances.
The yield ceiling here is wherever bank deposit rates sit. As of June 2026, the best business savings rates have been running around 4.3% AER. The money is simple, familiar, and covered by the UK's statutory safety net.
Route 2: Money market funds (MMFs)
An MMF pools your cash with other investors and buys short-term, high-quality instruments: government bills, bank paper, top-grade corporate debt. The yield tracks the market more closely than bank deposits, which is why MMF yields have often run ahead of savings rates in a higher-rate environment.
The key distinction: MMFs are not bank deposits. They are regulated investment products. Your money is held in segregated assets, so a provider failure does not put client cash on the balance sheet, but the underlying instruments carry their own credit risk. FSCS deposit protection does not apply to the fund itself. The phrase to know is "asset protection, not FSCS."
For most high-quality, sterling MMFs (think BlackRock ICS, Fidelity, J.P. Morgan AM), the actual probability of loss is extremely low, and the funds are designed to maintain a stable net asset value. But this is a different risk model from a deposit, and it is important to understand that before choosing.
What to weigh before deciding
| Question | Why it matters |
|---|
| How much? | FSCS matters most above £120k at a single institution; deposit platforms solve this by spreading |
| How often does it move? | MMFs and instant-access accounts both offer daily liquidity; fixed-term deposits do not |
| Is this purely parked cash, or does it also fund operations? | If you need to pay suppliers or payroll from it, integration matters as much as rate |
| How much time do you have? | Managing multiple bank relationships yourself takes real admin time |
| What is your regulatory context? | Some organisations (charities, regulated entities) have constraints on MMF use |
The ranked list: 9 options compared
The nine options below represent the realistic shortlist for a UK business in 2026. They are not ranked purely by yield, because yield is only one variable. They are ordered roughly from "most protection-focused" to "most yield/ops-integration-focused" so you can scan the list in the direction that matches your priorities.
1. Flagstone
What it is: A UK cash deposit marketplace. You sign up once, complete KYC, and then access a menu of instant-access, notice, and fixed-rate savings accounts across 40-plus FCA-regulated partner banks. A holding account (HSBC) sits behind the platform.
Typical yield (2026): Fixed 12-to-24-month accounts have been showing around 4.30% to 4.40% AER on the business platform (rates from flagstoneim.com/business, fetched June 2026). Instant-access rates for personal savers have been advertised up to around 4.20% AER. Rates displayed are net of Flagstone's interest margin.
Protection model: FSCS-eligible per partner bank, up to £120,000 per banking group. Spreading across many banks is the core value proposition. All partner banks are FCA-regulated.
Minimum (business): £100,000. There is no published maximum.
Who it suits: Companies and organisations with a large lump sum, typically £100k or more, that want FSCS coverage at scale without managing 10 separate bank relationships. Charities, property firms, and businesses that sit on significant working capital for months at a time.
Where it fits: If protecting capital across FSCS is your primary goal and you have £100k or more to place, Flagstone is hard to beat on simplicity and coverage. It is a passive tool: money sits, it earns, it does not move or do anything else. You cannot pay a supplier from it.
2. Insignis Cash
What it is: A deposit marketplace and managed cash service, operated by Insignis Asset Management Limited (FCA-regulated). Similar model to Flagstone: spread deposits across a network of partner banks, one KYC, one dashboard. Insignis adds a designated account manager service to guide clients on where to place and when to switch. Worth knowing: Insignis is also the deposit-spreading partner behind Round's own Savings product, so choosing Insignis directly versus Round's Savings option is largely a question of whether you want the extra automation, AP, and payroll Round layers on top, rather than a different underlying bank network.
Typical yield (2026): Bank deposit rates, which track the current savings market. Insignis does not publish a standard rate table publicly in the same way as Flagstone; rates are competitive with the deposit market. Check insigniscash.com/business-savings for current offers.
Protection model: FSCS per partner bank, same mechanism as Flagstone.
Minimum: Not publicly confirmed. Contact Insignis directly. The platform is positioned for companies, charities, trusts, and local authorities, which suggests a meaningful minimum.
Who it suits: Businesses and organisations that want FSCS-spread deposits and value human support in managing placement: finance teams that would rather have a conversation than work a dashboard.
Where it fits: Very similar to Flagstone in structure; the main differentiator is the account-manager relationship and the client types it specifically courts (charities, trusts, local authorities alongside companies). If managed service matters, Insignis is worth a direct conversation.
3. Akoni Cash Management
What it is: A savings platform for businesses and individuals, offering instant-access, notice, and fixed-rate accounts across multiple providers including Investec, Aldermore, Barclays, and Charter Savings Bank.
Typical yield (2026): Bank deposit rates, in line with the savings market. Specific rates vary by the partner banks on offer, so check current rates with the provider.
Protection model: FSCS-eligible per partner bank.
Minimum: Not publicly confirmed. Contact Akoni directly.
Who it suits: SMEs that want a straightforward multi-bank deposit spread without a high entry point or managed-service overhead.
Where it fits: Akoni is consistently named alongside Flagstone and Insignis in UK comparison sources as a third business deposit platform. Fewer public details are available than for Flagstone. If the others do not fit your size or you prefer a different provider mix, Akoni is worth investigating.
4. Direct business savings accounts
What it is: Opening a savings account directly with a bank or building society. Providers in the UK business savings market include Cambridge and Counties Bank, Redwood Bank, Allica Bank, Tide, Hampshire Trust Bank, Shawbrook, and United Trust Bank, among others.
Typical yield (2026): The best business savings rate as of mid-June 2026 was approximately 4.3% AER (source: moneyfactscompare.co.uk). Aggregator sites such as money.co.uk have advertised rates up to 4.4%. Rates vary significantly by account type (instant access, notice, fixed) and by provider.
Protection model: FSCS, up to £120,000 per banking group for eligible businesses.
Minimum: Varies by provider and account type, from a few hundred pounds to tens of thousands.
Who it suits: Businesses that want the simplest possible setup, are comfortable with one bank relationship, and hold under £120k (or are comfortable with single-institution concentration above that). Also suits businesses that want to keep everything inside an existing banking relationship.
Where it fits: The highest-rate direct savings accounts are often smaller, specialist banks you may not have heard of. The headline rates are competitive with deposit platforms but you are managing the relationship yourself, and you lose the spreading benefit unless you open multiple accounts.
5. TreasurySpring
What it is: A wholesale-grade cash platform offering Fixed-Term Funds (FTFs). Each FTF gives you maturity-matched exposure to a single investment-grade issuer, covering government bills, bank deposits, and corporate paper. Terms run from one week to one year; currencies include GBP, USD, EUR, and more. There are over 1,000 products across eight currencies.
Typical yield (2026): Money-market-style yields that reflect the specific issuer and term chosen. Rates are not published as a headline figure; they depend on which FTF you select and when. Check treasuryspring.com for current offers.
Protection model: Not standard FSCS. Credit risk sits with the chosen counterparty (the issuer of the FTF), not with TreasurySpring as a platform. All obligors are investment-grade. There is no "run risk" in the way an open-ended MMF can face one, because each FTF is fully maturity-matched: your investment and the underlying asset settle on the same date. This is a different and arguably more transparent risk model than a pooled MMF, but it is explicitly not FSCS-covered deposit protection.
Minimum: TreasurySpring is understood to have a substantial minimum; figures are not publicly confirmed and should be verified directly. The platform is designed for corporates, SMEs, family offices, and charities with meaningful treasury balances.
Who it suits: Finance teams that want institutional-grade, risk-tiered cash management with clear visibility of exactly what they are exposed to, and who are comfortable moving beyond the standard deposit/MMF binary.
Where it fits: TreasurySpring is the most sophisticated option on this list for companies that want to actively manage the credit quality and duration of their cash portfolio. It requires more active attention than a deposit platform and is not for cash you need to access unpredictably. Verify the minimum directly before considering it.
6. Wise Interest
What it is: Wise holds your balance in an interest-bearing product that invests in money-market-style assets. Available as part of the Wise multi-currency business account.
Typical yield (2026): GBP interest of around 3.23% variable (as of late March 2026, per Bloomberg reporting). Rates are variable and will move with the market.
Protection model: MMF-style asset protection, not FSCS. Wise is regulated by the FCA and safeguards client funds, but the mechanism is asset protection, not deposit insurance.
Minimum: Low. The product is accessible to Wise Business account holders without a large minimum balance requirement.
Who it suits: SMEs that are already using Wise for multi-currency payments and FX, and want to earn something on GBP or other currency balances without moving money to a separate platform.
Where it fits: The GBP yield trails the best business savings accounts and deposit platforms on this list. The value case is convenience: if you already move money internationally through Wise, keeping a working balance earning yield there makes sense. It is not the highest yield option.
7. Revolut Business Flexible Cash Funds
What it is: A feature within Revolut Business that lets you invest spare company cash into Fidelity money market funds (available in GBP, EUR, and USD). Yield accrues daily and the aim is capital preservation.
Typical yield (2026): Variable, tracking MMF market rates. The exact GBP yield is not confirmed in our research at time of writing. Check Revolut Business directly for current rates.
Protection model: MMF protection, not FSCS. Your money is in regulated investment funds, not a bank deposit.
Minimum: Low. Accessible to Revolut Business account holders.
Who it suits: Revolut Business users who want to earn yield on idle balances without leaving the Revolut platform. If your team uses Revolut for cards, expenses, and FX, parking surplus cash in Flexible Cash Funds requires zero extra onboarding.
Where it fits: Like Wise, the convenience case is strong if you are already on Revolut Business. The product does not offer the integration depth or automation that a treasury-first platform provides, and the GBP yield needs to be confirmed against current alternatives before assuming it is competitive.
8. Airwallex Yield
What it is: Launched March 2026, Airwallex Yield routes idle cash into a J.P. Morgan AM government money market fund. Available to Airwallex business account holders. There is no lock-up period.
Typical yield (2026): Up to 3.40% APY on idle USD (since March 2026, per Airwallex's own blog). The GBP yield figure is not confirmed in our research at time of writing. Check airwallex.com directly for current GBP rates.
Protection model: MMF protection, not FSCS. No lock-up.
Minimum: Low. Available to Airwallex account holders.
Who it suits: Scaling businesses that use Airwallex for global payments and multi-currency operations, and want to earn yield on their operating cash without a separate treasury setup.
Where it fits: Airwallex is a genuinely broad platform (cards, expense, AP, FX, and now yield), which makes it relevant for companies that want operational breadth alongside treasury. If your business operates globally with complex multi-currency needs, Airwallex is one of the stronger all-in options. The GBP yield should be verified before comparison.
9. Round
What it is: Round is a UK finance automation platform that sweeps idle cash into the BlackRock ICS Sterling Liquidity Fund (a AAA-rated institutional money market fund) as part of a broader system that also handles accounts payable, UK payroll, multi-entity cash visibility, and FX. You do not need to manage the sweep manually: Round handles the cash movement and can fund your payment runs directly from your treasury balance.
Typical yield (2026): Round's claim is "4x average yield on idle cash versus a standard business savings account" (roundtreasury.com), reflecting the net daily yield from the BlackRock ICS Sterling Liquidity Fund. Round doesn't publish one fixed rate: net AER varies by plan tier and loads live on the pricing page, moving with the money market, so check roundtreasury.com/pricing for the current figure rather than a number printed in a comparison article.
Protection model: Round offers two routes. Its Savings product (via Insignis) provides FSCS-protected deposits spread across UK partner banks, up to £120,000 per institution and up to £3.5m in aggregate, the same model as Flagstone. Its money market route (the BlackRock ICS Sterling Liquidity Fund) is asset protection, segregated and institutional-grade, not FSCS, and your capital is at risk. Round holds customer assets in segregated accounts with regulated partners, including BlackRock as fund manager, and does not hold customer money on its own balance sheet.
Minimum: Contact Round directly. Not publicly confirmed on the site.
Who it suits: Finance teams, founders, and CFOs at growing UK companies that want yield on idle cash but also need to automate how that cash moves: paying suppliers, running payroll, managing multiple entities. If you are currently keeping cash in a low-yield bank account because moving it feels like admin, Round is designed for that problem. The platform connects to Xero and NetSuite, so payments reconcile automatically.
Where it fits: Round is not the right choice if your sole objective is the highest FSCS-protected rate and you have no interest in automating your finance operations, though its own Savings product can meet the FSCS need if you'd rather stay on one platform. Round is the right choice if you want MMF-grade yield and you also want to stop doing manually what a system should do: fund a payroll run from your treasury balance, auto-code and pay invoices, and see all your cash in one place.
Comparison table
| Option | Mechanism | Typical yield (2026) | Protection model | Minimum | Best for |
|---|
| Flagstone | Deposit marketplace (40+ FCA banks) | ~4.30-4.40% AER fixed; ~4.20% instant (Jun 2026, flagstoneim.com) | FSCS per bank (£120k each) | £100,000 (business) | Large lump sums, FSCS spread at scale |
| Insignis Cash | Deposit marketplace + account manager | Competitive deposit rates (check insigniscash.com) | FSCS per bank | Not publicly confirmed | Managed FSCS placement; charities, trusts, local authorities; also powers Round's own Savings product |
| Akoni | Deposit marketplace (Investec, Aldermore, Barclays, Charter and others) | Competitive deposit rates (check provider) | FSCS per bank | Not publicly confirmed | SMEs wanting multi-bank deposit spread |
| Business savings accounts | Direct deposit, single bank | Best ~4.3% AER (mid-Jun 2026, moneyfactscompare.co.uk) | FSCS per institution (£120k) | Varies by provider | Simplest option; single relationship, smaller balances |
| TreasurySpring | Fixed-Term Funds: maturity-matched exposure to single investment-grade issuers | MMF-style yield (varies by issuer/term, check treasuryspring.com) | Credit risk to chosen counterparty; not FSCS | High (confirm directly) | Corporate treasurers wanting risk-tiered, transparent cash management |
| Wise Interest | MMF-style interest product, multi-currency | GBP ~3.23% variable (late Mar 2026, Bloomberg) | MMF asset protection; not FSCS | Low | Wise users earning yield on working balances |
| Revolut Business Flexible Cash Funds | Fidelity MMFs (GBP/EUR/USD) | Variable (GBP rate: check revolut.com) | MMF asset protection; not FSCS | Low | Revolut Business users, daily-accrued yield on spare cash |
| Airwallex Yield | J.P. Morgan AM government MMF | Up to 3.40% APY (USD, since Mar 2026); GBP: check airwallex.com | MMF asset protection; not FSCS; no lock-up | Low | Global SMBs on Airwallex, multi-currency ops |
| Round | MMF (BlackRock ICS Sterling Liquidity Fund) + full finance ops automation | "4x vs standard business savings" (roundtreasury.com); net AER shown live on pricing page | MMF asset protection on treasury product; not FSCS. Round's own Savings product (Insignis) is FSCS-eligible up to £120k per institution, £3.5m aggregate | Contact Round | Finance teams wanting yield AND automated AP/payroll/multi-entity ops |
How we would choose
There is no single right answer, so here is how we think through it by situation.
You have a large lump sum to protect
If you are sitting on £500k or more and your priority is FSCS coverage at scale with competitive rates, Flagstone or Insignis are built for exactly this. Flagstone's £100k business minimum and 40-plus bank network gives you meaningful spread. Insignis adds a managed-service layer if you want guidance on placement. These are passive tools: the money earns, it does not move, and that is the point.
You want the highest available yield on a deposit
Check the direct business savings market at moneyfactscompare.co.uk or money.co.uk. As of June 2026, the best business rates have been around 4.3% AER. The catches: you manage a direct relationship yourself; FSCS covers only £120k per institution; and fixed-term accounts tie up liquidity. Deposit platforms such as Flagstone shave a small margin but handle the relationship management for you.
You already use a fintech for payments and want effortless yield
If you are already on Wise, Revolut Business, or Airwallex, the path of least resistance is enabling their yield products and earning on your working balance without opening a separate account. The yields are competitive with, or slightly below, the best deposit platforms, and the convenience trade is real. Just be clear you are in MMF territory, not FSCS territory, for these products.
You want institutional-quality yield with explicit credit-risk control
TreasurySpring is for finance teams that want to know exactly what paper they hold, choose the issuer and duration, and actively manage the credit profile of their cash book. This requires more active attention and a meaningful balance. If that matches your setup, it is worth a conversation.
You want yield and you also want to stop managing your finance function manually
This is where Round sits. If you are currently keeping cash idle in a low-rate account because sweeping it somewhere better feels like one more thing to manage, or if you are running payment approval by forwarding emails and chasing people on WhatsApp, Round addresses both at once. The BlackRock ICS Sterling Liquidity MMF generates yield daily; the platform handles invoice capture, approval routing, payroll funding, and reconciliation to your accounting system. The treasury yield is MMF-grade, not FSCS-protected deposit (Round's separate Savings product covers that need if it matters more to you), so understand the difference before you move cash. If the "idle cash" problem and the "too much manual finance work" problem are the same problem for you, they can be solved together.
Related reading
Explore Round
If you are holding idle business cash in a low-rate account and want to understand what an automated treasury setup would look like for your business, you can get started at roundtreasury.com.
