A New Tax System (Goods and Services Tax) (Attribution Rules – Prepayment for a Telecommunication Supply) Determination 2026

This is a tax rule about when phone and internet companies must pay GST on money they receive before sending a bill.

What it does: Normally, businesses pay GST in the tax period when they issue an invoice or receive payment (whichever comes first). But telecom companies often receive prepayments — money paid upfront by customers before any bill is issued. This rule fixes a timing problem: without it, the company might have to pay GST immediately upon receiving the prepayment, even though they haven't issued an invoice yet.

The fix: For telecom companies that don't use cash accounting (meaning they account for GST when invoices are issued, not when cash is received), GST on prepayments is now due in the earlier of:

• The tax period when they actually issue the invoice; or
• The tax period when they would have issued the invoice if the customer hadn't prepaid.

Who it affects:

• Telecommunications providers (phone, internet, mobile companies) that receive upfront payments from customers
• Customers — indirectly, as this affects how providers manage their tax cash flow

Why it matters: This prevents telecom companies from being forced to pay GST on money received before their normal billing cycle kicks in. It aligns the tax timing with their actual business practices. The rule also an older 2016 rule that did the same thing, updating the framework without changing the underlying policy.