Capital Gains Tax on Share payout

As the disposal is between 1st January 2015 - 30th November 2015, the CGT amount will have to be paid by 15th December 2015.

The CGT return will not be required to be filed until 31st October 2016 and is included as part of the Form 12 as your mother is a PAYE worker. She won't be able to complete this until she receives a P60 from her employer for 2015 as these details are also required on the Form 12.

The above assumes your mother is not a self assessed individual in which case the form to be completed is Form 11 (PAYE workers with non-PAYE income of more than €3,174 are regarded as self assessed individuals)

CGT rate is 33% and is charged on the gain that arose from the share sale. An allowance is given for the original cost of the shares and depending on year of purchase can be indexed to factor in inflation. Also, the first €1,270 of taxable gains in a tax year are exempt from CGT.

Might be best to get in contact with an accountant/tax advisor as there is more to it than just handing over a percentage of what she got.

Just get an accountant to file it for you and do the calculations