Employer Identification Number
The IRS requires business owners to obtain an Employer Identification Number, sometimes referred to as a Tax Identification Number, when they start up a business. Most states use a company's federal EIN for tax reporting purposes, but a few states issue a separate state tax identification number to each company. Even though the IRS requires an employer to obtain an EIN, you are not required to report that number on your federal tax return if your employer neglects to provide the information. You can still file your tax return without it.
If you received Form W-2 from your employer, your employer's federal or state identification number is likely listed on the form. Form W-2 shows compensation for your employment and your federal, state and local tax withholdings for the year. Some states do not have a state or local income tax, so those fields may be left blank. The IRS requires you to submit a copy of your W-2 along with your federal tax return. If your employer's federal EIN or state tax identification number is not on the form, that is not your responsibility. You can still file your return with a missing identification number.
If you are not too close to the deadline for filing your tax return, you can complete Form W-9 and submit it to your employer. Form W-9 is available online at the IRS website. Form W-9 is an official request for a tax identification number from your employer. You can send the form to your employer by mail, or you can request the information in person. Even though the IRS does not require you to provide the number on behalf of your employer, including the information along with your tax return makes processing your return easier and faster.
State and Local Income Tax
State tax withholdings are tax deductible on your federal return. The IRS allows you to combine state and local income tax and itemize that expense as a deduction on Schedule A of tax Form 1040. If your employer neglects to include a state identification number on your W-2 for state taxes withheld during the year, you can still claim the deduction. It is your employer's responsibility to provide the necessary identification numbers, and the IRS does not penalize you for his mistake.