According to the U.S. Small Business Administration Office of Advocacy, the U.S. contains 36.2 million small businesses. For the accountants, bookkeepers, and attorneys who support these millions of entrepreneurs, the Employer Identification Number (EIN) is the primary thread that connects every financial and legal action a business takes. This nine-digit number acts as the business’s tax identity, and it is necessary for everything from opening a payroll account to filing a simple tax return.
While an EIN is permanent, it is surprisingly easy for business owners to lose track of the original paperwork. As a professional, you are often the one tasked with finding this number so you can keep a client’s project moving forward. Whether you are setting up a new banking relationship or cleaning up years of back taxes, you need a reliable way to verify this number without wasting hours on hold or falling for third-party scams. The Internal Revenue Service (IRS) is the only official source for these numbers, and there are three specific ways you can recover a lost EIN through official channels.
1. Check IRS Paperwork and Confirmation Notices
The most efficient place to start is with the documents the IRS sent when the business first started. When a business owner or their representative applies for an EIN, the IRS issues an official notice. This is usually called the CP 575 notice, and it is the definitive proof of the EIN assignment. If the application happened online, the applicant was given the option to download this notice as a PDF immediately. If the application was sent via mail or fax, the IRS would have mailed a physical copy to the business address on record.
The Taxpayer Advocate Service advises that looking for this original notice should always be your first step. It contains not just the EIN, but also the exact legal name of the entity as it exists in the IRS database. This is a critical detail because even a small mismatch in a business name can cause a tax return to be rejected or a bank account application to be denied. You should ask your client to look through their founding documents, such as their Articles of Incorporation or their initial corporate binder, where these notices are often kept.
One common point of confusion for professionals is whether they can get a “new” original notice. It is important to remember that the IRS does not issue duplicate copies of the original CP 575 assignment notice. If the client has lost that specific piece of paper, it is gone for good. However, you can request an alternative called Letter 147C. This letter is the IRS’s way of verifying an EIN that was previously assigned. It carries the same weight as the original notice for almost all legal and financial purposes. If a bank or a state agency insists on seeing the “original” notice, providing Letter 147C will satisfy their requirement for official verification.
2. Review Business Records, Tax Returns, and Other Official Files
If the original IRS notice is nowhere to be found, you can usually find the EIN by looking through the business’s own historical files. This is often the fastest way for a bookkeeper or accountant to solve the problem without having to wait for government correspondence. The EIN is a working number, meaning it should be stamped or typed on dozens of documents that the business has already handled.
Your first stop should be the most recent federal tax returns. For a corporation, check Form 1120. For a partnership, look at Form 1065. If the business has employees, the EIN will be prominently displayed on Form 941, the Employer’s Quarterly Federal Tax Return. Because these forms are legal filings, the number listed on them is highly likely to be the correct one.
Beyond tax forms, the IRS suggests checking bank statements and account applications. No bank in the U.S. will open a business account without an EIN, so the bank will have it on file. You can often find it by logging into the client’s online banking portal and looking at the “Account Details” or “Tax Information” section. Additionally, check for any state or local business licenses. Whether it is a liquor license, a health department permit, or a general city operating permit, the application likely required the EIN. If you are an attorney, you might also find the EIN in the business’s annual reports filed with the Secretary of State, though some states do not require the EIN to be listed on public-facing corporate records. Checking these secondary sources allows you to verify the number quickly so you can continue with your compliance work.
3. Contact the IRS to Confirm the EIN or Request Verification
When all internal searches fail, the final and most authoritative option is to contact the IRS directly. The IRS maintains a specific department for these inquiries known as the Business & Specialty Tax Line. You or your client can call 800-829-4933 to ask for an EIN search. This line is open from 7:00 a.m. to 7:00 p.m. local time, Monday through Friday.
There is a specific process for this call to ensure the security of the business’s information. The IRS agent will not give the EIN to just anyone. If the business owner calls, they must be prepared to verify their identity by providing their Social Security number, date of birth, and the legal address of the business. If you are an accountant or attorney calling on behalf of a client, you must have a valid Form 2848 (Power of Attorney) or Form 8821 (Tax Information Authorization) already on file with the IRS. If the authorization is not in their system, the agent cannot disclose the number to you.
During this call, you should specifically ask for a Letter 147C. While the agent can tell you the number over the phone, having the physical letter is much better for long-term recordkeeping. The agent can often fax this letter to you while you are still on the phone if you have access to a secure fax line. This provides an immediate, official paper trail that you can add to the client’s permanent file. Relying on this direct IRS contact ensures that you are not guessing and that the records you are building for your client are 100% accurate.
What to Do if You Still Cannot Find It
In some rare cases, even a call to the IRS might not produce a number. This usually happens if the business was never actually assigned an EIN or if it was registered under a different legal name than the one you are searching for. If this happens, do not turn to third-party websites that promise to find your EIN for a fee. Many of these sites are simply trying to charge you for services that the IRS provides for free, or worse, they are looking to harvest sensitive business data.
The IRS is very clear that there is no charge for an EIN or for verifying an existing one. If the IRS has no record of the business, you may need to apply for a new number. However, you should only do this after a thorough search, as having multiple EINs for the same legal entity can cause significant tax processing issues later on. Always use the official IRS support path to resolve these discrepancies.
When an EIN May Need to Change
As a professional advisor, you need to know when a client can keep their current EIN and when they are legally required to get a new one. The IRS guidelines for changing an EIN depend mostly on the structure of the business rather than its daily operations.
In simple terms, you generally do not need a new EIN if the business is just changing its name or moving to a new location. In those cases, the existing number stays the same, and you simply notify the IRS of the change. However, you do need a new EIN if the business structure or ownership changes in a fundamental way. For example, if a sole proprietor decides to incorporate, or if a partnership is taken over by one of the partners and becomes a sole proprietorship, the old entity technically ceases to exist for tax purposes and a new one is born. This new entity requires its own EIN. Staying on top of these rules ensures that your clients are always filing under the correct identity, which prevents “mismatched” notices and potential penalties from the IRS.
Frequently Asked Questions
How can I find my EIN if I lost the original IRS notice?
Check your previous tax returns, business bank statements, or any licenses issued by your city or state. If you cannot find it there, call the IRS at 800-829-4933.
Can I find my EIN on a prior business tax return?
Yes. Every federal business tax return requires an EIN. You can find it in the entity information section at the top of forms like the 1120 or 1065.
Will the IRS give me the original EIN assignment notice again?
No. The IRS does not send out duplicate CP 575 notices. Instead, they provide Letter 147C as an official replacement for verification purposes.
What is Letter 147C, and when is it used?
Letter 147C is an official IRS letter that confirms a business’s EIN. It is used when a bank or other agency requires proof of the EIN but the original notice has been lost.
Can my bookkeeper or accountant call the IRS to confirm an EIN?
Yes, but only if they have a Power of Attorney (Form 2848) or a Tax Information Authorization (Form 8821) on file with the IRS.
Is there a fee to look up or recover an EIN from the IRS?
No. The IRS provides all EIN-related services for free. You should never pay a third-party website to look up or apply for an EIN.
Where else might an EIN appear besides IRS paperwork?
Look at your business credit report, payroll service records, 1099-NEC forms you have issued to contractors, or your application for a business bank account.
Does a business name change require a new EIN?
No. If you change your business name, you can keep your existing EIN. You just need to follow the IRS procedures for reporting a name change.
Does a business address change require a new EIN?
No. A change of address does not require a new EIN. You should file Form 8822-B to let the IRS know your new location.
When should a business get a new EIN after a structure or ownership change?
A new EIN is usually required if you change the legal structure of your business, such as moving from a partnership to a corporation or if a new charter is required.
Managing the administrative side of a business is often a heavy lift for entrepreneurs. As their advisor, your goal is to make these processes as seamless as possible so they can focus on growth. Keeping a secure, organized record of essential numbers like the EIN is a simple step that prevents major headaches during tax season or during a business audit.
If you are looking for a way to keep your clients’ financial records more organized, MagicBooks can help. It is a bookkeeping solution designed to help professionals and businesses keep their data clean, accessible, and ready for any compliance task. By using a dedicated system for financial management, you ensure that important records are never more than a click away.
