You can apply for a new EIN when you already have one, but only if a change in your business’s legal structure or ownership has created what the IRS treats as a new entity. Most routine changes, including a new name, a new address, a new line of work, or new employees, do not qualify. The old EIN stays with the old structure, and a fresh number is issued only when a genuinely different taxpayer exists.
When a New EIN Is Required
The trigger depends on what kind of entity you started with. The common thread is that a new legal entity, or a materially different tax situation, has come into existence.
Sole Proprietors
A sole proprietor needs a new EIN after incorporating the business, forming a partnership, or filing for bankruptcy. Incorporation creates a new legal person under state law. A partnership shifts the business to joint ownership and a different tax regime. Personal bankruptcy creates a separate bankruptcy estate that files under its own identification.
Partnerships
A partnership needs a new EIN if it incorporates, if one partner takes over the business and runs it as a sole proprietorship, or if the partners dissolve the existing partnership and start a new one. A change in ownership that does not terminate the partnership under tax law does not require a new number.
Corporations
Corporations need a new EIN when they receive a new charter from the secretary of state, begin operating as a subsidiary of another corporation, convert to a partnership or sole proprietorship, or merge with another corporation to form a brand-new entity. Mergers are where people slip: the surviving corporation keeps its existing EIN, and a new EIN is only required when the merger produces a new corporation.
LLCs
An LLC needs a new EIN if it is terminated and replaced by a new corporation or partnership. A single-member LLC that needs to file employment or excise tax returns also needs its own EIN, even if the owner already has one from another source.
If you are the sole owner of an LLC with no employees, no excise tax obligations, and no election to be taxed as a corporation, you do not need a separate EIN at all. You can use your Social Security Number or an existing sole proprietor EIN. Adding a second member generally causes the LLC to be treated as a partnership for federal tax purposes, and that new partnership needs its own EIN.
Changes That Do Not Require a New EIN
Many changes feel significant but leave the legal entity intact. In these cases your existing EIN carries forward:
- Changing the business name or address. Update the IRS on your next return or with Form 8822-B.
- Changing what the business does, including a full pivot into a new industry.
- Hiring or laying off employees. The EIN is tied to the entity, not the headcount.
- Running multiple businesses as one sole proprietor under the same legal identity.
- Electing S corporation status by filing Form 2553. The corporation keeps its EIN.
- Surviving a merger. The absorbing corporation keeps its number.
- Corporate reorganizations that change identity or location without creating a new legal entity.
- State-level conversions that do not change the federal tax classification.
- Bankruptcy filed by a corporation or partnership. Only sole proprietors need a new EIN after bankruptcy.
- Converting a partnership to an LLC that is still classified as a partnership for tax purposes.
One case that catches sole proprietors off guard: if a spouse joins the business but you continue filing as a sole proprietorship, the EIN stays the same. Separately, if the person the IRS has on file as the “responsible party” changes, you do not get a new EIN; you file Form 8822-B within 60 days to update the record.1Internal Revenue Service. About Form 8822-B, Change of Address or Responsible Party – Business
How to Apply When You Do Need a New One
Applications go on Form SS-4, and you have four ways to submit it.2Internal Revenue Service. About Form SS-4, Application for Employer Identification Number (EIN)
- Online is fastest. The IRS issues the EIN immediately once the application is complete.3Internal Revenue Service. Get an Employer Identification Number
- Fax takes about four business days.
- Mail takes about four weeks.
- Phone is available only to applicants without a legal residence, principal office, or principal place of business in the United States.
The IRS issues only one EIN per responsible party per day.3Internal Revenue Service. Get an Employer Identification Number If you are standing up several entities at once, plan on consecutive days.
Closing Out the Old EIN
An EIN is permanent. Once assigned, it is never reused for another entity, and the IRS cannot cancel it. What the IRS can do is close the business account tied to the number so it is no longer treated as an active filer.4Internal Revenue Service. If You No Longer Need Your EIN
To close the account, send the IRS a letter with the full legal name of the business, the EIN, the business address, and the reason for closing. Include a copy of the original EIN assignment notice if you still have it. The IRS will not close the account until all required returns have been filed and all taxes owed have been paid.5Internal Revenue Service. Closing Your Business
Skipping this step after a restructuring can leave the old account open, which sometimes produces notices or compliance letters years down the line.
What Filing Under the Wrong EIN Costs
Filing with an outdated or incorrect EIN causes real problems. An electronically filed return with a mismatched number is typically rejected, and you have to correct and resubmit. If the IRS contacts you about the mismatch and you do not respond promptly, additional tax assessments, penalties, and interest can follow.
The penalties on information returns like W-2s and 1099s are steep. For returns due in 2026, the IRS charges $60 per incorrect return corrected within 30 days, $130 per return corrected between 31 days and August 1, and $340 per return corrected after August 1 or never corrected. Intentional disregard raises the penalty to $680 per return.6Internal Revenue Service. Information Return Penalties For a business filing dozens or hundreds of information returns, the totals climb quickly, which is why sorting out the EIN question at the moment of a structural change is worth the effort.