Starting a business

Hi, I have a quick question:

Can my wife (a non-EEA national), start a business in Ireland if she is on a temporary Stamp 4? Can she do it when she is on a EU4Fam?

Yes, as long as you are resident in Ireland and exercising a Treaty right or have acquired the right of permanent residence (assuming you are an EEA national).

Yes, I'm an Irish-born Irish national, who has exercised my EU Treaty Rights in another EU member state, and my wife is therefore entitled to apply for Stamp EU4Fam