Revenue has issued eBrief No. 75/16 (see here) which confirms that the iXBRL filing deadline has been extended to within three months of the Form CT1 filing date. The concessional 21 day extension will be increased to three months in respect of accounting periods ending on 1 December 2015 or later.

The extension will apply from the due date of the Form CT1. If the iXBRL return is filed later than three months after the due date, a late filing surcharge of 10% of the corporation tax due will apply.

It should be noted that the 21 day concession continues to apply to iXBRL returns submitted where the accounting period ends on 30 November 2015 or earlier.

The due date for filing the Form CT1 is not affected by this extension. Accordingly, to ensure that surcharges are not incurred, Forms CT1 should be filed on or before the appropriate due date. The iXBRL filing extension will not change the existing practice whereby repayments are held pending receipt of the iXBRL return.

We continue to engage with Revenue on iXBRL matters. The continued exposure to a 10% surcharge on taxpayers who have otherwise filed and paid their taxes on time is disproportionate. You can read more on the iXBRL filing requirements for companies and updates on our iXBRL web centre.