When You DO Need a New EIN
You must obtain a new EIN when your business structure changes in a way that creates a new legal entity. Common cases:
1. Sole Proprietor → LLC
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A new EIN is required if the LLC has more than one member or is treated as a corporation.
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A single-member LLC (disregarded entity) usually requires a new EIN unless the owner already had employees or excise taxes under the sole proprietorship.
2. Sole Proprietor → Corporation (C-Corp or S-Corp)
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Always requires a new EIN.
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The corporation is a separate legal entity from the individual.
3. Partnership → Corporation
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Requires a new EIN because the ownership and taxation structure fundamentally change.
4. Partnership → LLC (multi-member treated as partnership)
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A new EIN is required because the legal entity changes, even if taxation stays similar.
5. LLC → Corporation
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Requires a new EIN if the LLC incorporates.
6. Any Entity → New Partnership
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Forming a partnership due to adding new owners changes the entity.
When You Do NOT Need a New EIN
A new EIN is not required when the business structure changes only for tax purposes, without a new legal entity being formed.
Examples:
1. Single-Member LLC (SMLLC) → Start hiring employees
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No new EIN required.
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The existing EIN is used for payroll tax registration.
2. LLC Elects S-Corporation Tax Status (Form 2553)
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The structure remains an LLC.
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IRS treats the LLC as S-Corp for tax purposes only, no new EIN.
3. Corporation Elects S-Corporation Status
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Same corporation, new tax election.
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No new EIN.
4. Ownership changes within the same entity
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Buying or selling ownership interests does not trigger a new EIN.
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The entity remains the same legal organization.
Special Cases
Nonprofit restructuring
A nonprofit usually keeps its EIN even through leadership changes, but:
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Merging with another nonprofit
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Reincorporating in another state
may require a new EIN.
Trusts
Some trust restructurings require new EINs, especially when:
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A trust becomes irrevocable
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A new grantor replaces the original
Quick Reference Chart
| Change | New EIN Required? |
|---|---|
| Sole Proprietor → LLC | Sometimes |
| Sole Proprietor → Corporation | Yes |
| Sole Proprietor → Partnership | Yes |
| LLC → Corporation | Yes |
| LLC → S-Corp (tax election) | No |
| Corporation → S-Corp | No |
| Corporation → LLC | Yes |
| Partnership → LLC | Yes |
| Partnership → Corporation | Yes |
| Internal ownership change | No |
| Adding employees | No |
Source:
https://www.irs.gov/businesses/small-businesses-self-employed/when-to-get-a-new-ein