Why BAS Deadlines Matter For Australian businesses registered for GST, lodging a Business Activity Statement (BAS)  on time is a legal obligation. Your BAS reports GST, PAYG withholding, PAYG instalments, and other taxes. Deadlines vary based on whether you lodge monthly, quarterly, or annually. Missing the due date can lead to costly penalties, interest and unnecessary stress. Consequences of Lodging Your BAS Late 1. Failure to Lodge Penalties The ATO can issue a Failure to