As far as i am aware (and apologies if someone else has already posted this information) the cut off for the declaration of shares is €13,000.

If you check the form that they have to fill out on the oireachtas website then you will see this.

Therefore a TD could have shares under this amount and does not need to declare them. Therefore ones that do hold shares under the threshold amount should really answer n/a when they have answered none or nil.