“Do I need a merchant account?” is one of the first questions new businesses ask when they start looking at card readers. The answer is more useful once you know what a merchant account actually is — because the term means different things depending on who’s using it, and most small businesses don’t need one in the traditional sense at all.
What a merchant account is
A merchant account is a type of bank account that sits between your customer’s bank and your own. When a customer pays by card, the money doesn’t go straight to your business account. It first lands in the merchant account held by your acquiring bank, where it’s held briefly while the transaction clears, then forwarded on to you.
Merchant accounts are opened by acquiring banks — financial institutions that take on the risk of processing card payments on your behalf. Until relatively recently, this was the only way for any business to accept card payments. You applied to an acquiring bank, went through an underwriting process, signed a contract, and (if approved) were assigned a merchant account. Approval could take weeks. Decline was possible.
How modern card readers changed this
Providers like Square, SumUp, Zettle, and Stripe don’t give each business its own merchant account. Instead, they operate as payment aggregators — or payment facilitators (PayFacs) — holding a single large merchant account that thousands of businesses share.
When you sign up to Square and start taking payments, you’re processing under Square’s merchant account. Square handles the acquiring relationship with the card networks. You never speak to an acquiring bank, you don’t go through underwriting, and you can start taking payments the day you sign up.
This is why you can set up a card reader in an afternoon and take your first payment the same day. The aggregator model has removed almost all of the friction from starting.
The trade-off: because aggregators take on the risk for thousands of businesses, they protect themselves with higher transaction rates than a dedicated merchant account and — occasionally — account holds if a transaction pattern looks unusual. An account hold is rare for typical small businesses, but it happens, and when it does your funds are frozen while verification is completed. Responding promptly to any verification request with the documentation asked for usually resolves it within a few days.
When do you actually need a dedicated merchant account?
For most small businesses, you don’t. An aggregator handles everything you need.
A dedicated merchant account is worth considering in two situations.
First, if your monthly card turnover is consistently above roughly £10,000–£15,000 per month. At that volume, a dedicated acquiring relationship with negotiated rates can reduce your transaction costs meaningfully. Worldpay, Barclaycard, and Takepayments all work this way. You go through an application process, get a tailored rate, and pay less per transaction. The trade-off is contracts, minimum monthly charges, and less flexibility.
Second, if your business operates in an industry that aggregators consider higher-risk. Adult content, gambling, travel, firearms, pharmaceuticals, and some subscription businesses can find their accounts closed or held with aggregators. A dedicated merchant account from a specialist acquirer handles these categories more reliably.
For everyone else — sole traders, cafés, market stalls, retailers, tradespeople, salons — an aggregator is the sensible starting point and probably where you’ll stay.
The payment gateway: a separate but related concept
A payment gateway is different from a merchant account, though the two are often discussed together. The gateway is the technology that transmits card data securely during a transaction — the encrypted pipe between your card reader (or checkout page) and the processing network.
With modern app-based card readers like Square and SumUp, the gateway is built in. You don’t configure it or pay for it separately. It’s part of the service.
If you’re building a custom ecommerce setup and need a standalone gateway, that’s a different conversation — Stripe, Opayo (formerly Sagepay), and Worldpay all offer gateway products independently of card reader hardware.
Aggregator vs dedicated merchant account: the key differences
| Aggregator (Square, SumUp, Zettle) | Dedicated merchant account | |
|---|---|---|
| Application required | No — sign up online | Yes — underwriting process |
| Time to first payment | Same day | Days to weeks |
| Contract | None | Typically 12–18 months |
| Transaction rate | 1.69–1.75% (standard) | Lower, negotiated (varies) |
| Monthly fees | None on PAYG plans | Minimum monthly service charge |
| Account holds | Possible if activity looks unusual | Less common |
| Best for | Under ~£10,000/month | Above ~£10,000/month or higher-risk |
Does the type of account affect how customers pay?
No. Customers tap, insert, or wave their card regardless of whether you use an aggregator or a dedicated merchant account. The difference is entirely behind the scenes — how the money flows, how quickly it settles, and what fees are deducted along the way.
Our verdict
For a new or small UK business starting to take card payments: sign up with an aggregator. Square, SumUp, or myPOS will have you taking payments today without an application, a credit check, or a contract.
Revisit a dedicated merchant account once you’re consistently above £10,000/month and the lower negotiated rates would meaningfully reduce your costs.
See our how card readers work guide for how the full payment chain connects, or our guide to choosing a card reader if you’re still deciding which provider fits.
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