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Established in Newport in 1869 to help local people build homes, we now help people across Wales and England buy properties and save for their future.
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Maturity 5 Year Fixed Rate ISA

Issue 1


Interest Rate AER / Tax Free - Fixed3.87%

Minimum - Maximum Balance : £1,000 to £2,000,000

Open and manage your account : Online, in Branch or Agency

You must be:

  • You must be a Monmouthshire Building Society customer with a maturing Fixed Rate Cash ISA to open this account.

May be suitable for you if: 

Green Check Mark PNGs for Free DownloadYou would like to invest a lump sum for 5 Years.

Green Check Mark PNGs for Free Download You do not need access to your money for 5 Years.

Green Check Mark PNGs for Free Download You have £1,000 available to open the account. 

Green Check Mark PNGs for Free Download You would like to manage this account online and/or in person from

        Monmouthshire Building Society Branches.

Not Suitable for you if:

 File:Cross red circle.svg - Wikimedia Commons  You would need access your funds within the fixed period.

 File:Cross red circle.svg - Wikimedia Commons  You would like to open this account over the phone or by post.

Additional Information:

  • Accounts can be held in sole name only.
  • Additional funds can be added whilst the product is on sale (up to the annual ISA subscription limit, £20,000 for the 2025/26 tax year).
  • There is a 14-day cancellation period.
  • There may be a penalty if you withdraw your money before the end of the fixed term. (Full closure, including transfer to another ISA provider, will be allowed subject to 450 days’ loss of interest, calculated on the closing balance.)

Click below to expand the Maturity 5 Year Fixed Rate Cash ISA Summary Box and Terms and Conditions.

What is the interest rate?
  • 3.87% AER / Tax-free * calculated daily and paid on maturity.
  • Interest is fixed for 5 years.
Can Monmouthshire Building Society change the interest rate?
  • No. The interest rate is fixed, so we can’t change it during the term.
What would the estimated balance after 5 years (60 months) based on £1,000 deposit?
  • £1,209.07
  • We have worked this out assuming a £1,000 deposit is made, no further deposits or withdrawals are made during a 5-year period and the interest is added to your account.
How do I open and manage my account?

Ways to open

  • You can open this account to transfer funds from a maturing Monmouthshire Building Society Fixed Rate Cash ISA by following the instructions received with your maturity letter.

Who can open

You must be:

  • You must be a Monmouthshire Building Society customer with a maturing Fixed Rate Cash ISA to open this account.

Open from

  • The minimum amount to open this account is £1,000.
  • The maximum balance is £2,000,000.
  • Additional deposits can be made as often as you like up to the maximum ISA allowance, while the product is on sale.

Manage your account

  • You can manage your account at any branch or agency, by post or online (if registered with our ‘My Accounts’ service).
Can I withdraw money?
  • No, during the term, you can’t take any money out of your account.
  • Full closure, including transfer to another ISA provider, will be allowed subject to 450 days’ loss of interest, calculated on the closing balance.
Additional Information 
  • Interest is paid tax-free.
  • You will only need to pay tax on any savings income you earn above your Personal Savings Allowance.
  • The Personal Savings Allowance applies to the total savings income you earn from all banks/building societies and not just from Monmouthshire Building Society. Visit HMRC website at www.hmrc.gov.uk for more information.
  • AER stands for Annual Equivalent Rate and illustrates what the interest rate would be if interest was paid and compounded each year.
  • The tax-free rate is the rate of interest payable where interest is exempt from income tax.
  • Rates and information correct as of 13 June 2025.

It is important that you read the following before deciding to open an account:

Maturity 5 Year fixed Rate Cash ISA

Maturity Fixed Rate Cash ISA Terms and Conditions

Other Important Information:

Savings terms:

AER stands for Annual Equivalent Rate and shows what the interest rate would be if interest were paid and added to your account each year.

Gross is the rate of interest payable before any tax is taken off.

Fixed interest means the rate stays the same until the account matures.

Variable interest means the rate can go up or down at any time. We will always publish our rate changes and give you with at least 30 days notice if the rate on one of your accounts is due to go down.

Tax-free means you will not pay any tax on your interest.

Tax year runs from 6 April to 5 April.

Business day is Monday to Friday excluding bank holidays.

The information provided in the summary box is a summary of the key features of the Maturity 5 Year Fixed Rate Cash ISA and is not intended to be a substitute for reading the terms and conditions above that apply to the account.

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