There is only one file type that uses the .TA4 extension:
TaxAct 2014 Tax Return File
2014 tax return created with the 2014 version of TaxAct; contains tax data for the 2014 tax year; includes both federal IRS tax forms and state forms for a specific state.
The TA4 file is most often created during 2015 since annual tax returns are filed for the previous year. You can import a TA4 file for filing your 2015 taxes as it allows you to import previous tax information. Be aware that when you import a TA4 tax return into TaxAct, any data that has been entered will be overwritten by the data from the TA4 file.
A TA4 file can be saved by the desktop version of TaxAct or exported from TaxAct Online. Once you have completed a tax return, you can either print and mail the tax forms or file electronically.
Updated: October 25, 2015