Assuming that it is just your name on the Australian bank account as a co-signer, and he is the true owner of the account, then the answer to your question would be no, Form 8938 would not be required of you (although this form may be required to be filed by your husband, if he is a resident alien or dual citizen for US tax purposes).
That said, there are, in fact, two
separate disclosure forms that may be required for US taxpayer with foreign financial assets; each also has different
reporting rules. One is known as IRS Form 8938, and can be
attached to the relevant yearly Form 1040 tax return. The other is FinCen
Form 114, which can only be filed via the internet. The following Internal
Revenue Service webpage describes them in some detail, and provides their
dollar value reporting levels:
https://www.irs.gov/businesses/comparison-of-form-8938-and-fbar-requirements
Form 8938 is included in
TurboTax. FinCen Form 114 is not included in TurboTax, and you would need
to access that reporting webpage separately, if your foreign financial assets
total over the limit(s). Note that you can get to the FinCen reporting
internet site directly through the above IRS link.
In an important piece of information directly related to your original question, if the balance in your husband's Australian bank account was larger than $10,000 (US Dollars) at any point during the calendar year, then even as a co-signer on the account (even in the absence of any ownership interest), FinCen Form 114 will be required of you. This is because FinCen Form 114 is applicable to all those who have signing power over a foreign account (that is, they have the authority to move money), which is different than the rules underlying IRS Form 8938.
Thus, for all of these reasons, please read the
IRS.gov webpage (link above) carefully. The US government has been particularly vigilant in enforcing these foreign account disclosure rules in recent years.
Thank you for asking this important question.
