Corporate tax return (CT600)

The Corporate Tax return CT600 is the form that limited companies must complete and submit annually to HM Revenue and Customs (HMRC) to report their Corporation Tax liability.  

Here's a breakdown:

Part of the Company Tax Return

The CT600 form is the main component of a company's full Company Tax Return. This return also includes the company's statutory accounts, tax computations, and any supporting documents, claims, or elections.  

Reporting Taxable Profits

The CT600 details the company's income, allowable deductions, and calculates the taxable profits for a specific accounting period (usually 12 months).

Calculating Corporation Tax

Based on the taxable profits, the form is used to calculate the amount of Corporation Tax the company owes to HMRC, applying the relevant Corporation Tax rates.  

Legal Requirement

All companies registered in the UK and liable for Corporation Tax are legally required to file a CT600 annually, even if they haven't made a profit. HMRC will typically issue a "Notice to Deliver a Company Tax Return," which specifies the filing deadline.  

Online Filing

Since April 2011, it has been mandatory for most companies to file their CT600 online through the HMRC Online Services or via commercial accounting software that is compatible with HMRC's system. The accompanying accounts and computations must also be submitted online in a specific digital format called iXBRL (inline eXtensible Business Reporting Language).  

Deadlines

The deadline for filing the Company Tax Return (including the CT600) is generally 12 months after the end of the company's accounting period. However, the deadline for paying the Corporation Tax liability is usually earlier, typically 9 months and 1 day after the end of the accounting period (unless the company is large and pays in instalments).

Penalties for Late Filing

Failure to submit the CT600 by the deadline can result in penalties from HMRC, which increase the longer the return is outstanding.  

In essence, the CT600 is the official document used by companies to declare their profits and calculate their Corporation Tax obligations to HMRC.

It's a crucial part of complying with UK tax law