12.2 Employer Identification Number (EIN)
Key Takeaways
EIN = business "SSN" (9-digit federal tax ID).
Required if: employees, corporation, partnership, retirement plan.
Sole prop: SSN sufficient unless employees or retirement plan.
New EIN required: incorporation, death of sole prop, new partnership.
NOT required: name change, S-election, check-the-box.
Responsible Party change: report within 60 days (Form 8822-B).
Why This Matters for the Exam
EIN requirements are frequently tested. Know when a new EIN is required vs. when the old one continues.
When EIN Is Required
| Trigger | EIN Required |
|---|---|
| Have employees | Yes |
| Corporation or Partnership | Yes |
| Trust or Estate (Form 1041) | Yes |
| Retirement plan (Keogh, 401k) | Yes |
| Excise tax returns | Yes |
| Sole prop (no employees) | SSN sufficient |
When NEW EIN Is Required
| Change | New EIN? |
|---|---|
| Sole prop incorporates | YES |
| Death of sole proprietor | YES (for estate) |
| Partnership terminates, new forms | YES |
| Corporation receives new charter | YES |
When NEW EIN Is NOT Required
| Change | New EIN? |
|---|---|
| Name change | NO |
| Address change | NO |
| C-Corp elects S-status | NO |
| LLC check-the-box election | NO |
| Partnership adds partner | NO (usually) |
Form SS-4
| Method | Details |
|---|---|
| Online | Fastest (Mon-Fri 7am-10pm EST) |
| Fax/Mail | Required if no US SSN/ITIN |
| Third-party designee | EA/CPA can apply on behalf |
Responsible Party Rule
| Element | Requirement |
|---|---|
| Definition | Individual with control over funds/assets |
| Change reporting | 60 days (Form 8822-B) |
| Risk | Outdated info = notices to wrong person |
Real-World Scenario
Scenario: In 2025, a sole proprietor incorporates and receives a new state charter.
- Old EIN: Cannot continue (different legal entity).
- Action: Apply for new EIN using Form SS-4.
- Timeline: Immediate upon incorporation.
On the Exam
Question types to practice on EIN:
- New EIN Questions: "Sole prop incorporates—new EIN?"
- Responsible Party Questions: "How many days to report change?"
- S-Election Questions: "Does S-election require new EIN?"
The key is to remember: New EIN if structure changes (incorporation, death). Same EIN if name/address/S-election. Responsible Party = 60 days.
Sole proprietor incorporates with new state charter. New EIN required?
C-Corp S-election = new EIN
Partnership moves states
Sole prop incorporates = new EIN
LLC changes name
Deceased sole proprietor business continues 6 months. EIN requirement?
Use deceased SSN
Obtain EIN for Estate
Use executor SSN
Convert SSN to EIN
Responsible Party changes. Report within how many days?
30 days
60 days
90 days
120 days
Sections you finish are checked off in the contents.