This deadline relates to transactions that occurred in the month of December 2014.
If you sold, gifted or transferred an asset between 1st December and 31st December 2014 then the CGT is payable on 31 January 2015.
If you are tax resident or ordinarily resident in Ireland and domiciled in Ireland the liability arises on worldwide gains.
Payment of CGT is triggered by the date of the unconditional contract.
Revenue has issued a reminder.