What interest rate does the Cynergy Bank 1 Year Fixed Rate Cash ISA pay?

The Cynergy Bank 1 Year Fixed Rate Cash ISA pays 4.05% AER fixed.

How much interest could I earn?

Saving £10,000 for 1 year would earn about £405 at 4.05% AER. This assumes the rate stays the same and interest stays in the account.

How much can I pay in?

You can deposit at least £500.

When is interest paid?

Interest is paid on each anniversary of opening.

Who can open this account?

New and existing Cynergy Bank customers can open it. You can open it online.

Is my money protected?

Yes. Eligible deposits are protected by the Financial Services Compensation Scheme (FSCS) up to £120,000 per person, per banking licence.

Can I transfer an existing ISA in?

Yes, transfers in from other ISAs are accepted.

How does it compare with other one-year cash ISAs?

At 4.05% AER it ranks 52nd of 61 one-year cash ISAs we track. The best pays 4.98% and the average is 4.45%.

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Cash ISA Compare 1 Year Fixed Rate Cash ISAs

Cynergy Bank 1 Year Fixed Rate Cash ISA Review

A one-year cash ISA from Cynergy Bank. It ranks 52nd of 61 one-year cash ISAs we track.

Rate checked Oct 2026Got this account? Leave a review

Fixed rate · 1 year

4.05%AER

Rate checked Oct 2026Got this account? Leave a review

Protection

FSCS£120,000

Min balance

£500

Max balance

No limit

Term

1 Year

Interest paid

Anniversary

Transfers in

Accepted

How It Stacks Up

Ranks 52nd of 61

1-year cash ISAs we track

Below average

This account 4.05%

UK CPI (Aug 2026): 3.10%; Pays 0.95% more
Average 1-year cash ISA: 4.45%; Pays 0.40% less
Best 1-year cash ISA: 4.98%; Pays 0.93% less

Inflation: ONS. Averages and best rates: accounts on DepositScout.

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Pros and cons

Pro: New and existing savers
Con: Not flexible: money you withdraw can't be replaced without using more allowance

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Estimated returns with Cynergy Bank's Cash ISA

What you could earn with Cynergy Bank's 1 Year Fixed Rate Cash ISA.

Estimated interest

£1,000 saved

£40.50

At 4.05% AER

£5,000 saved

£202

At 4.05% AER

£10,000 saved

£405

At 4.05% AER

£50,000 saved

£2,025

At 4.05% AER

Estimated over one year, if the rate stays the same and interest is left in. Amounts outside the account's minimum or maximum aren't shown.

Our Expert Opinion on Cynergy Bank 1 Year Fixed Rate Cash ISA

Jonny PeaseCo-Founder, DepositScout

Cynergy Bank's 1 Year Fixed Rate Cash ISA pays 4.05%, which is below the market average for cash ISAs and 1.20% behind the category leader at 5.25%, so I would not call this rate particularly strong. It does at least beat August 2026 CPI of 3.1% by 0.95%, meaning your money grows in real terms. The minimum is £500 and interest is paid on anniversary, but early closure costs you 180 days of interest. Leek Building Society's 1 Year Fixed Rate Cash ISA at 4.55% is worth a look first.

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