With effect from 30 October 2024, the main rates of CGT applying to disposals of assets other than residential property and carried interest increased from: 

• 10% to 18% for basic rate taxpayers; and 
• 20% to 24% for higher rate taxpayers. 

As explained in an earlier article, the SA tax return may not automatically calculate CGT liabilities at the increased main rates. In this case, the taxpayer will need to make an adjustment to their return. HMRC has provided an online calculator that can help with this.  

HMRC is writing to taxpayers who have declared a disposal made on or after 30 October 2024 on their 2024/25 SA tax return and who appear to have an made an error in calculating the amount of CGT due. The taxpayer will receive one of the following letters depending on their circumstances: 

• Letter one: the return includes an adjustment, but it appears to be incorrect.
• Letter two: the return does not include an adjustment and it appears that an incorrect rate of CGT has been used. 

The taxpayer is asked to take the following action within 30 days of the letter:

• check the return using HMRC’s tool to work out the correct adjustment; and
• either:
  • if the return is incorrect, amend the return; or
  • if the return is correct, contact HMRC using the details given in the letter.

HMRC will charge interest on any CGT paid late. The letter also sets out the next steps if no action is taken by the deadline given by HMRC in the letter.