How long should tax professionals hold onto the e-file signature authorizations of their clients? It depends on where they and their clients reside.

Form 8879, “IRS e-file Signature Authorization,” is signed by 1040 taxpayers to, among other things, authorize the electronic return originator to electronically file the taxpayer’s federal tax return. EROs must retain the signed copy of the Form 8879 for three years from the return due date or date the return is filed, whichever comes later. Most states that accept electronic filing of individual tax returns have their own version of an e-file signature authorization form that serves the same purpose as the federal form.

Most states require retention of the state e-file authorization form for three years, like the federal retention period. However, for some states that three-year period is defined differently than the federal three-year retention period. For example, Indiana’s IT-8879 must be retained three years from Dec. 31 of the year it is signed, while Louisiana’s LA8453 must be retained three years from Dec. 31 of the year the return is due. The District of Colombia’s D-40E SUB and New Mexico’s PIT-8453 must be retained three years from the calendar year in which the return is filed.

The retention periods for the Arizona, California, Colorado and Michigan forms are outliers: The retention periods for the California CA8453, Colorado’s CO DR8453 and Arizona’s AZ-8879 are different formulations of a four-year period; and the Michigan MI-8453 must be retained for six years.

The Missouri Department of Revenue requires that the MO-8453 be retained by the ERO but does not set a minimum retention period.

Because electronic filing of the individual tax return for most states is mandatory for tax professionals, it is important for the tax professional to know the e-file signature authorization form retention rules imposed by the various states. Below is a chart that lists those retention rules.