There are no reporting requirements to Revenue for any specific withdrawals/thresholds. Some institutions do take a particularly rigid (mis)interpretation of Anti-Money Laundering requirements and ask all sorts of questions in relation to certain activity but generally withdrawals should none of their business - they may ask for source of funds for things like cash lodgements > €X,000. Large withdrawals can raise a flag if they are part of a wider pattern of activity that raise a suspicion of money laundering and could result in an institution submitting a suspicious transaction report to Revenue and the Gardaí.