The CT600K is the restitution tax supplementary page to the Company Tax Return. It reports restitution interest that HMRC has paid the company and the 45% Corporation Tax charge on it.
Who completes it
A company that HMRC paid restitution interest in the return period. Broadly, that is interest on a claim that tax was paid under a mistake of law or was unlawfully collected, where the claim has been finally decided or settled and the interest is not simple interest at a statutory rate. Ordinary repayment interest does not count. Very few companies ever need the page. Box 141 on the CT600 is ticked to say it is attached.
What it asks for
- The interest for each financial year the return falls in, and the tax on it at 45%.
- The tax already withheld by HMRC when it paid the interest (K25).
- The restitution tax now payable, which goes to box 527 on the CT600.
The charge stands on its own. Losses, group relief, capital allowances and other reliefs cannot reduce it. HMRC normally withholds the 45% when it pays the interest, so in most cases nothing more is due.
In Tax Optimiser
Complete the page under Restitution Tax in the Corp Tax workspace. The computation is not adjusted for you: if the interest is in the profit and loss account, deduct it there so that it is not taxed twice. The CT600K is filed with the CT600.
Read more: CT600K and restitution tax.