HMRC has confirmed it is changing the way it will handle tax on bank and building society interests.

What has HMRC changed?

Since October 2025, HMRC has been sending out Simple Assessment letters to individuals who may owe tax on interest incurred from banks and building societies between April 2024 and April 2025.

The letters clarify the exact amount of tax owed on the interest during the 2024/25 tax year, why you owe that amount and how to pay your tax bill.

You may have received an initial Simple Assessment letter, but HMRC may send another to you if your bank or building society has provided updated information to the tax authority that includes any accrued interest.

If you have already paid following a first letter, you will need to calculate the outstanding debt and pay that off.

It’s important to remember that banks and building societies report the interest you receive to HMRC each year, meaning that even though you didn’t declare it, HMRC is aware and the letter outlines what you need to do.

What if the figures don’t match?

You don’t need to be concerned if the figures from your tax code and bank statements do not match what is shown, as a number of factors may be taken into consideration.

These include some interest on your personal savings allowance that can be tax-free, only taxable interest is included in your tax codes and when preparing assessments, HMRC may be estimating figures based on the data available to them.

You can contact HMRC directly to dispute the letter, but this must be done within 60 days of receiving the letter.

If you are unsure about a Simple Assessment letter you’ve received, our team of experienced accountants can help you review it, check that it has been reported correctly and outline the steps you need to follow to ensure HMRC is satisfied.

Contact us today for expert advice and support.