By when should you submit financial statements in iXBRL format along with CT600 and what is the penalty for delay 
Every business entity required to file their company tax returns must prepare, at the end of its financial year:
Please bear in mind that you still need to file your company tax returns even if your company has made a loss, or if you have no Corporation Tax to pay.
You have different deadlines for sending your accounts to Companies House and your tax return to HMRC, but you may be able send them at the same time. If your company is small, a micro entity or dormant, you might be able to send simpler (‘abridged’) accounts.
You need your accounts and tax return to meet deadlines for filing with Companies House and HM Revenue and Customs (HMRC).
The table below sets out the deadline for different filings :
| Action | Deadline |
| File first accounts with Companies House | 21 months after the date you registered with Companies House |
| File annual accounts with Companies House | 9 months after your company’s financial year ends |
| Pay Corporation Tax or tell HMRC that your limited company does not owe any | 9 months and 1 day after your ‘accounting period’ for Corporation Tax ends |
| File a Company Tax Return | 12 months after your accounting period for Corporation Tax ends |
Your accounting period for Corporation Tax is the time covered by your Company Tax Return. It is normally the same 12 months as the company financial year covered by your annual accounts.
You can file with Companies House and HMRC together or separately. Additional steps are required
The table below sets out the penalty applicable for late filing of corporation tax :
| Late By | Applicable Penalty |
| One day | £100 |
| three months | additional £100 |
| six months | HMRC will calculate the corporation tax due and will add a penalty of 10 percent of the unpaid corporation tax |
| twelve months | additional 10% of the unpaid corporation tax |
