An Employer Identification Number cannot be changed. Once the IRS assigns that nine-digit number to a business, it stays with that entity permanently. So when people ask how to change an EIN number, they are really asking one of two questions: do I need to apply for a new EIN, or can I just update the information the IRS has on file for the one I already have? The answer depends on whether your business’s legal structure has changed. A structural change means a new EIN. Almost everything else, including a new name, new address, or new owner of record, is handled as an update under your existing number.
When You Need a New EIN
The IRS requires a new EIN whenever the legal structure of the business changes. If the entity becomes something fundamentally different in the eyes of the law, the old number does not carry over.1Internal Revenue Service. When to Get a New EIN
For a sole proprietorship, that means incorporating or taking on a partner. For a corporation, it means receiving a new charter from the Secretary of State, creating a subsidiary, merging with another corporation into a new entity, or converting to a sole proprietorship or partnership. Partnerships need a new number when one partner takes over the business alone, when the partnership incorporates, or when the existing partnership ends and a new one forms to continue operations.
Limited liability companies follow the same principle: a change in legal structure triggers a new EIN. Changing only the LLC’s tax classification, such as electing to be taxed as a corporation or S corporation, does not.
When You Keep Your Existing EIN
Many changes people assume require a new number do not. You keep your existing EIN when you:
- Change your business name
- Change your business address or physical location
- Change your responsible party
- File for bankruptcy
- Elect S corporation status
- Convert at the state level without changing the underlying structure (for example, from a domestic LLC to a foreign LLC)
- Experience a change in partnership ownership, as long as the partnership itself is not terminated and a new one formed
In each of these cases, the underlying entity is still the same taxpayer, and the IRS wants you to update your records rather than start over.1Internal Revenue Service. When to Get a New EIN
How to Apply for a New EIN
When a new number is required, you apply on Form SS-4. The form asks for your entity’s legal name as it appears on formation documents, any trade name or DBA, the type of entity, why you are applying, and the date the business started or its structure changed.2Internal Revenue Service. Instructions for Form SS-4 (12/2025)
The line that trips up most applicants is the responsible party. This has to be an actual person who owns or controls the entity, identified by Social Security Number or Individual Taxpayer Identification Number. It cannot be another business, and it cannot be a nominee given limited authority just for formation purposes. If a nominee was listed by mistake on an earlier application, correct the record with Form 8822-B.3Internal Revenue Service. Responsible Parties and Nominees
The IRS accepts applications three ways, with very different turnaround times:
- Online, through the IRS EIN assistant, gives you your number immediately at the end of the session. The tool is available Monday through Friday from 6:00 a.m. to 1:00 a.m. (next day), Saturday from 6:00 a.m. to 9:00 p.m., and Sunday from 6:00 p.m. to midnight Eastern time.4Internal Revenue Service. Get an Employer Identification Number
- By fax, with a return fax number on your SS-4, the IRS usually sends back your EIN within four business days.
- By mail, expect about four weeks.
If your principal place of business is outside the United States, the online tool is not available to you. International applicants can apply by phone at 267-941-1099 (Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern time), by fax to 304-707-9471, or by mail to Internal Revenue Service, Attn: EIN International Operation, Cincinnati, OH 45999.5Internal Revenue Service. Employer Identification Number
How to Update Your EIN Record Without a New Number
If your legal structure has not changed, you update the information the IRS has on file. The process depends on what changed.
Address or Responsible Party
Use Form 8822-B to notify the IRS of a new business mailing address, a new physical location, or a change in responsible party. A change of responsible party has to be reported within 60 days.6Internal Revenue Service. About Form 8822-B, Change of Address or Responsible Party – Business Your EIN does not change.
Business Name
The name change route depends on entity type.7Internal Revenue Service. Business Name Change
A sole proprietor writes to the IRS at the address where the most recent return was filed, with the letter signed by the owner or an authorized representative.
A corporation that has not yet filed this year’s return checks the name-change box on Form 1120 (Page 1, Line E, Box 3) or Form 1120-S (Page 1, Line H, Box 2). If the return is already in, send a letter signed by a corporate officer to the IRS address where the return was filed.
A partnership that has not yet filed checks the name-change box on Form 1065 (Page 1, Line G, Box 3). If already filed, send a letter signed by a partner to the same IRS address.
For any entity type, including a copy of your articles of amendment or other state documentation reflecting the name change helps the IRS process the update faster.
What to Do After You Get a New EIN
A new EIN issued partway through a year creates some cleanup work, especially if you took over an existing business.
Payroll and Employment Taxes
The IRS treats a business that takes over another employer’s operations as a successor employer. If the acquisition meets the IRS’s requirements, wages the predecessor paid to employees who continue working for you count toward the Social Security wage base limit ($184,500 for 2026) and the Additional Medicare Tax withholding threshold of $200,000, so the same wages are not taxed twice up to those caps. Comparable rules apply to the $7,000 FUTA wage base per employee.8Internal Revenue Service. Publication 15 (2026), (Circular E), Employers Tax Guide
W-2 reporting for a mid-year EIN change follows the procedures in Revenue Procedure 2004-53. That procedure lets a successor employer file a single W-2 for the full year in some circumstances; otherwise the predecessor and successor each file W-2s for the portion of the year they employed the worker.9Internal Revenue Service. General Instructions for Forms W-2 and W-3 (2026) Either way, your payroll filings go out under the new EIN, not the predecessor’s.8Internal Revenue Service. Publication 15 (2026), (Circular E), Employers Tax Guide
Notify Everyone Else Who Has Your Old Number
The IRS is not the only party that needs the new number. A missed update can cause rejected filings, frozen bank transactions, or payroll failures. Contact:
- Your bank and any lender, line of credit, or merchant services account tied to your EIN
- Your payroll provider, before the next pay run
- Your state department of revenue and unemployment insurance agency
- Clients and vendors who issue 1099s to you, by sending a fresh Form W-9
- Your business insurance carriers
State-level fees for filing articles of amendment or updating a business license vary by jurisdiction, so check with your Secretary of State and local licensing agency for current amounts.
If You’ve Just Lost Your EIN
Misplacing your EIN is not a reason to apply for a new one. The number is still active and permanently assigned to your business. Before doing anything else, try to recover it:5Internal Revenue Service. Employer Identification Number
- Find the original CP 575 confirmation notice the IRS sent when it issued the number
- Check any federal business tax return you have filed; your EIN is on every one
- Ask the bank where you opened your business account
- Ask any state or local agency you used for a business license
- Call the IRS Business and Specialty Tax Line at 800-829-4933 (Monday through Friday, 7:00 a.m. to 7:00 p.m. local time). After identity verification, the agent can give you the number over the phone or send Letter 147C confirming it.