Complete Form 1040X

• All W-2's are reported to the IRS, so eventually the IRS will determine this income to be unreported, unless a Form 1040X has been completed. Form 1040X is an "Amended Return" form used to correct forms 1040, 1040A, 1040EZ, 1040EZ-T, 1040NR, or 1040NR-EZ.
  
  

Deadline for Form 1040X

• The IRS requires that Form 1040X must be filed within three years of the date you filed the original return. or within two years after the date you paid the tax, whichever is later. The IRS will charge interest on any amount owed past the required filing deadline, including taxpayers who have filed an extension. Therefore, it is best to submit your amended form as soon as possible.
  
  

Impact on original return

• Depending on the total income reported on the original form versus the information on the amended return, you may be eligible for more or less than the refunded amount on the original return. If you receive a refund based on your original return, it is recommended that you do not cash the check until you have completed form 1040X and have determined the actual amount of what you owe or should expect for a refund.
  
  

Avoid missing information

• As tax documents arrive in the mail, keep them together in a secure location until it is time to prepare your return. Before completing your tax return, look through the tax documents to ensure that all of your wages have been accounted for on each W-2. If you have not received an expected W-2 form by Feb. 15, contact your employer first and then the IRS.