Inaccurate information on your business's tax return can delay its processing and even trigger an audit from the Internal Revenue Service. According to the Small Business Administration, a tax ID -- or Employer Identification Number -- identifies business entities to the IRS. There are different steps you can take to verify your own tax ID number if you can't locate it, or to find the tax ID numbers of other organizations.
Verify Your Own Tax Number
If you are not sure of your own EIN, you can call the IRS's Business and Specialty Tax Line maintained at (800) 829-4933. To receive the verification, you must be able to prove that you are an owner, partner or officer of the business, a trustee if the business is in a trust, or an executor if the business is in an estate. Businesses with bank accounts can contact the bank to confirm their own numbers, since banks require business customers to supply the number when opening an account.
Verify the Tax Number of a Nonprofit
If you want to claim a donation made to a charity as a tax deduction, you must make sure that it has nonprofit status with the IRS. The Exempt Organizations Select Check database maintained by the IRS lets you search for information on nonprofit organizations. Enter as much information as you can, such as the organization's name, city and state, to view the tax ID number. The IRS does not let you deduct donations made to for-profit organizations.
Verify a Business's Tax Number
Businesses that want to do business with you should complete a Form W9, Request for Taxpayer Identification Number and Certification. You will use the information on this form to fill out your Form 1099s that show income earned from your company. If the information is incorrect, the IRS can disallow your business expense deduction to the other company. You can visit the Secretary of State's website in the company's home state and look at the company's filings with the state to confirm its tax ID number. Publicly traded companies also must file documents with the Securities and Exchange Commission that you can look up to confirm their EINs.
Unlike Social Security Numbers, EINs are public information so you do not need the business' permission before verifying the number. If you need your own number, the IRS can mail a copy of the original certificate but will only mail it to the business address on file. If none of the above methods works, you might be able to find EINs by subscribing to fee-based research and data services such as Lexis and Westlaw.