Round vs Flagstone: which is right for your business cash? (2026)

In short: Flagstone is a UK deposit marketplace. It spreads your cash across 40-plus FSCS-regulated banks and earns fixed deposit rates (business rates have been running up to around 4.40% on a fixed term, as of June 2026), with a £100,000 business minimum. Round routes idle cash into an institutional money market fund for yield, and also runs your accounts payable, UK payroll, and multi-entity cash operations from the same platform. Round also offers its own FSCS-eligible Savings product for teams that want deposit-style protection rather than a fund. Flagstone wins on simplicity if FSCS-protected deposits are the whole job. Round wins if you want yield plus a finance function that runs itself.

What Flagstone is (and who it suits)

Flagstone is a cash deposit marketplace, not a bank. You sign up once, pass a single KYC check, and gain access to a menu of savings accounts from 40-plus FCA-regulated UK banks, all held through a central holding account (provided by HSBC). You move money between instant-access, notice, and fixed-rate accounts without reapplying at each bank. Flagstone makes its return by taking a margin on the interest before passing rates on to you.

The business proposition is simple: spread a large idle balance across multiple partner banks, keep each tranche below the FSCS protection limit per banking group, and earn better rates than a single high-street relationship can offer. As of June 2026, Flagstone advertises fixed-term business rates up to around 4.40% AER on 12-to-18-month terms. The business entry point is £100,000.

Flagstone is genuinely good at its one job. If you have a large sum sitting idle and your priority is FSCS-protected, multi-bank deposit coverage at competitive rates, Flagstone is built for that. It is used by SMEs, charities, wealth managers, and institutional clients across more than 7,500 business accounts, with over £20 billion under administration across its platform.

What Flagstone does not do: it cannot pay a supplier, fund a payroll run, reconcile an invoice, convert a currency, or automate any finance workflow. Money goes in. Money earns interest. That is the product.

What Round is (and who it suits)

Round is a finance automation platform: treasury yield, accounts payable, UK payroll, multi-entity cash visibility, and FX in one system, with AI agents that handle approval routing, cash sweeps, and payment execution.

On the yield side, Round sweeps idle cash into the BlackRock ICS Sterling Liquidity Fund, an institutional-grade AAA money market fund. Round states an average of 4x the yield of a standard business savings account. Rates move with the market and are shown live on Round's pricing page, so check roundtreasury.com/pricing rather than relying on a number printed here. Same-day liquidity is available for withdrawal requests made before 10:30am. Round holds customer assets in segregated accounts with regulated partners, including WealthKernel's investment infrastructure and BlackRock as fund manager, and does not hold customer money on its own balance sheet.

Crucially, Round is not a money-market-only platform. Alongside the fund, Round runs its own FSCS-eligible Savings product, built on Insignis, which spreads deposits across a network of UK partner banks in the same way Flagstone does, and carries the same FSCS protection: up to £120,000 per institution (assuming eligibility), extending to up to £3.5m in aggregate once spread across enough partner banks. So Round gives you a choice Flagstone cannot: FSCS-protected deposits, higher-yield money market funds, or both at once, inside a platform that also runs your AP, payroll, and cash operations. The comparison below covers both routes.

Beyond yield, Round handles the finance work that deposit platforms cannot touch. Invoices arrive by email, WhatsApp, or upload, get AI-coded and checked for duplicates, and are approved through configurable rules before Round pulls funds from treasury and settles on the due date, keeping cash invested until the last possible moment. Every payment syncs automatically to Xero or NetSuite. Payroll works the same way in reverse: Round doesn't calculate salaries, it pays what your existing payroll provider has already worked out. Upload the file, route approvals, and Round funds the run from treasury and executes on pay day.

Round also gives multi-entity finance teams a consolidated dashboard across UK, EU, and US bank accounts, with real-time cash positioning and live export to Google Sheets or a data warehouse. FX is priced by plan, from 0.50% on Launch down to as low as 0.10% on Enterprise, across GBP, USD, and EUR (Round's own marketing also cites a flat 15 basis point headline rate elsewhere, so confirm the rate that applies to your plan before assuming a single figure). Automated FX hedging is on the roadmap but not yet live.

Round also runs named AI agents live today, including the AI Treasury Manager, which sweeps funds between operating, payroll, and yield accounts based on thresholds you set, and the Account Opening Agent, which handles KYC routing to open savings accounts without manual resubmission. A Cash Positioning Agent is available on the Enterprise plan.

Round was founded in 2023 and raised a $6M seed round in April 2026, led by Alstin Capital alongside Backed VC, Love Ventures, and Passion Capital. Round Financial Limited is authorised and regulated by the Financial Conduct Authority (FRN 1050315), is also an agent of Plaid Financial Limited, and is an Introducer to Insignis Asset Management Limited. Round is ISO 27001:2022 certified. Named customers include Cleo and Notion Capital. Round's own Jack & Jill case study describes moving £14M in managed cash from 0.65% at Tide to 3.85% net yield, with four-plus hours saved per month on payment runs.

Round is built for UK finance teams that want idle cash working harder and the operational work automated: venture-backed companies, CFOs managing multiple entities, and founders who want to remove manual steps from payroll, AP, and treasury without stitching together five separate tools.

Side-by-side comparison

The risk trade: FSCS deposits vs money market fund

This is the most important section to read carefully before choosing.

Flagstone gives you FSCS-protected deposits. Every partner bank is FCA-regulated and FSCS-eligible. By spreading your balance across multiple banks, Flagstone keeps each tranche below the per-banking-group FSCS limit. If a partner bank fails, each protected tranche is covered up to that limit. That is one of the clearest forms of UK depositor protection available to a business.

Round's money market product gives you a fund, not a deposit account. The BlackRock ICS Sterling Liquidity Fund is an institutional AAA-rated fund investing in short-term, high-quality instruments. Your money is held in segregated accounts and does not sit on Round's balance sheet, but this is asset protection, not FSCS coverage. Round states plainly that your capital is at risk, and that FSCS does not cover e-money products.

Money market funds are widely used by UK corporates and finance teams for near-cash yield, and a AAA-rated fund has a strong structural track record. But the protection model is different from a bank deposit, and you should understand that before moving funds. If FSCS cover matters more to you than MMF yield, remember Round's own Savings product (via Insignis) offers the deposit-spreading route too, just as Flagstone does.

The like-for-like: on FSCS-protected deposits, Round matches Flagstone. Its Savings product uses the same partner-bank spread, up to £120,000 per institution and up to £3.5m in aggregate. Everywhere else the table is one-sided. Flagstone does deposits and nothing else: no accounts payable, no payroll, no multi-entity cash visibility, no FX, no AI agents. Round does all of it, and adds a higher-yield money market route on top. So the real question is not who protects deposits better, since both do, it is whether you want a single-purpose deposit marketplace or a finance platform that also protects deposits.

Neither platform is a replacement for your main bank account. Both are purpose-built for idle cash above a certain scale.

When to pick Flagstone

Flagstone is the right answer when:

• Your main job is parking a large sum (£100,000 or more) in FSCS-protected deposits at competitive rates, and you have no need for AP, payroll, or cash ops automation.
• You manage cash for a charity, trust, or institutional client where FSCS protection is a governance requirement.
• Your finance team is small and a simple, single-purpose savings platform is the easiest thing to onboard and explain to trustees or auditors.
• You want fixed-term rates rather than a variable money market yield.

Flagstone does its one job well. If that is your job, use Flagstone.

When to pick Round

Round is the right answer when:

• You want idle cash earning institutional-grade yield and you also need AP, payroll, or multi-entity cash management automated in the same system.
• You are a CFO or finance lead at a UK growth company managing cash across multiple entities, currencies, or bank relationships.
• You fund payroll or supplier runs from a central treasury balance and want to stop moving money manually between accounts before each run.
• You use Xero or NetSuite and want every payment reconciled automatically, without a manual step.
• You are comfortable with a money market fund protection model (asset-protected, not FSCS-deposit-insured) for the treasury product, or you'd rather use Round's own FSCS-eligible Savings option instead.

The clearest version of Round's case: Flagstone is excellent at one job, spreading a large balance across FSCS-protected banks. Round does that same job through its Savings product, and then keeps going: money market yield, accounts payable, UK payroll, multi-entity cash, FX, and AI agents that execute the work. Flagstone was never built to touch any of that. If a deposit marketplace is all you want, Flagstone is the simpler pick. If you want your cash protected and working while your finance operations run themselves, that is Round.

If you are running a finance team, not just parking a lump sum, the question is not "which has a better savings rate" but "which removes more manual work while keeping my cash working." That is Round's territory.

Related reading

• Best places to park idle business cash in the UK (2026): how Flagstone, Round, Insignis, TreasurySpring, and the major MMF platforms compare on yield, protection, and minimum.
• How Round automated payroll and AP for Jack & Jill: a real UK finance team moved £14M from 0.65% at Tide to institutional MMF yield and removed manual payment runs.

Ready to see Round in your finance stack? Book a demo: 30 minutes with the team, tailored to your entity structure and current stack.