Filing GST and locking periods

Nightbooks prepares your return; filing happens with IRD through myIR. Once you have filed, mark the return as filed in Nightbooks — that step matters more than it looks.

What marking-as-filed does

• Locks the period — transactions inside it can no longer be changed, so your filed return and your books stay permanently in agreement.

• Records the filed figures — the saved return becomes the period’s record, visible any time.

• Anchors the next return — the next period starts from a clean, agreed baseline.

Late claims

If something belonging to a locked period turns up later — a missed bill, a correction, an expense receipt found in a jacket pocket — code it normally. It flows into your next return as a late claim rather than silently rewriting a filed one. This is exactly how IRD expects small corrections to be handled.

If something big is wrong in a filed period

Material errors in a filed return are corrected with IRD (a GST101A or through myIR) rather than by editing history. Talk to your accountant for anything sizeable — and ask the AI accountant to quantify the difference first so the conversation is concrete.