Tax file numbers

Contributed by Annette Morgan and current to 27 July 2018

As a taxpayer, you are required to have a tax file number (TFN). Apart from serving as a means of identification of individual taxpayers, the number also helps the ATO in its collection of tax from revenue which may otherwise escape the tax net.

If you are an employee, you are required to provide your employer with your TFN and, subject to some exceptions, you must quote the TFN to investment bodies, such as banks, credit unions, building societies, companies issuing dividends, etc. Unless an exemption applies, if you do not quote your TFN, tax will be taken from interest, dividends, etc. at the top marginal tax rate plus the Medicare levy. The TFN amount deducted (commonly known as withholding tax) will reduce the amount of tax payable on your income from investments, but tax withheld for not quoting a TFN will not be refunded until a tax return is lodged.