What Is Form SS-4?
The Federal Employee Identification Number (EIN) also referred to as the form SS-4 is the primary document that an entity needs to fill out and duly submit to the Internal Revenue Service (IRS). You need the EIN if you want to open a business bank account, hire employees to work for you, set up payroll to start paying salary, apply for business licenses, file business tax returns, and start operations in a full-scale.
You mandatorily need the EIN to start initiating any of the above processes, so you have to apply for the EIN through the SS-4 well ahead, and not at the last minute. Once you submit the form, the IRS will peruse your details, and when they verify it, you will be assigned the EIN and communicated via a confirmation letter, referred to as CP 575.
Who Needs to File Form SS-4?
| Entity | Reason |
| Sole Proprietor | To obtain an EIN for tax filing, hiring employees, or establishing a business credit |
| Corporation (C or S Corp) | To report corporate taxes, set up payroll, and operate as a legal entity |
| Partnership | To file partnership tax returns and manage business activities jointly |
| Multi-member LLC | Required to get an EIN to file as a partnership or corporation |
| Trust | To report trust income or deductions to the IRS |
| Non-Profit Organization | To apply for tax-exempt status and file Form 990 series |
| Personal Service Corporation | To file corporate taxes and pay salaries for incorporated professionals |
| Employer Withholding for Non-Resident Foreign Person | To comply with IRS regulations on foreign income tax withholding |
| Foreign Business Entity | To conduct U.S. trade or open a U.S. bank account |
Filing form SS-4 should be on your top to-do list if you are a business that comes under the following eligibility criteria and wants to be recognized by the IRS as a legitimate entity.
- If you’re a sole proprietor who has set up your own business recently, for your taxes to be calculated appropriately, you need to submit form SS-4. Without it, you may have to use your social security number for all communications with the IRS, such as tax forms or invoices.
- Suppose you’re a corporation that needs to set up payroll and start paying salaries after withholding taxes, you can’t do so without an EIN, for which the SS-4 is mandatory. With an EIN, you can start paying employer contributions to social security and healthcare.
- If you’re changing from a sole proprietorship to a corporation LLC as you scale up, or have acquired a company recently, or merging two entities into one, a new EIN means the IRS recognizes you as a new entity, which is what you need for accurate tax classification.
- If you have a multi-member LLC, your main aim is to keep your personal finances separate from your business accounts. Having an EIN through a form SS-4 will help you do just that. Banks and other institutions typically require an EIN from you to open a business bank account under the LLC’s name, ensuring all financial transactions are properly tracked.
- For fiduciaries managing trusts or estates filing income tax returns, reporting income, and paying estate taxes are key legal responsibilities, and that is impossible to do without an EIN.
- As a non-profit organization, you definitely require an EIN to apply for tax-exempt status, or filing required returns. If you wish to apply for grants, donations, or other financial support, an EIN is compulsory.
- When you set up a personal service corporation, you must apply for an EIN using Form SS-4 because the corporation is a separate legal entity from the individual professional. Also, you must report income, expenses, and taxes under the PSC’s unique EIN. If you hire staff or pay yourself a salary from the corporation, you need the EIN for payroll and employment tax filings.
- If you’re an employer withholding taxes on income paid to a non-resident foreign person, you must apply for an EIN using Form SS-4 to file Form 1042 and Form 1042-S, which report U.S. source income paid to foreign persons, withhold and remit the appropriate federal tax to the IRS, and comply with FATCA or other international tax rules.
- Even without a physical presence or residence in the U.S., foreign entities may need an EIN if they engage in trade or business within the U.S., open a U.S. bank account or merchant processing account, and are required to file U.S. tax forms or withholding documents.
What Information Is Required on Form SS-4?
Filing the form SS-4 is crucial, so you want to get it right the first time. There are no calculations required per se, you just need to provide accurate information when filling out the form.
Here’s all the information you need to gather before you start filling out the form:
- The legal name of your entity or trust (as registered with state or legal authorities).
- A “doing business as” (DBA) or trade name, if applicable
- The name of the responsible party, such as the owner, trustee, or principal officer, their Social Security Number (SSN), Individual Taxpayer Identification Number (ITIN), or Employer Identification Number (EIN). This person must be an individual.
- The business or entity’s mailing address, and if different, its physical location
- Your entity type
- The accurate reason for applying for an EIN
- The date in which you commenced your business
- The closing month of your accounting year (determine this in advance, preferably when you form the business)
- Estimated number of employees in the next 12 months
- The name and phone number of the person the IRS can contact for questions
- Details of your accountant or attorney if they are helping you out in filling the form SS-4 and answering questions on your behalf
How Do You Fill Out Form SS-4?
Now that you are armed with all the information you need for form SS-4, let’s go over it line by line, with the instructions you require to fill out each line.
| Line | What to enter |
| 1 | Legal name of the entity or individual applying (e.g., your business or trust name) |
| 2 | Trade name, or Doing Business As name |
| 3 | Executor, administrator, trustee, and ‘care of’ name |
| 4a/4b | Mailing address – street, city, state, ZIP code |
| 5a/5b | Physical location |
| 6 | County and state where the entity is located |
| 7a/7b | Name and Social Security Number, of the responsible party |
| 8a | Enter if the applicant is an LLC |
| 8b | Number of LLC members |
| 8c | Enter if the LLC was formed in the US |
| 9a | Choose the appropriate entity type |
| 9b | For corporations – state or foreign country of incorporation |
| 10 | Reason for applying for an EIN |
| 11 | Date of start of business |
| 12 | Closing month of your accounting year |
| 13 | Maximum no of employees you expect to have in the next 12 months |
| 14 | Enter if you expect to pay $1000 or more in taxes |
| 15 | First-date wages or annuities |
| 16 | Principal business activity |
| 17 | Do you want to file Form 944 annually instead of quarterly Form 941 |
| 18 | Applied for or received an EIN before? |
Line 1: Enter your official business name. If you’re a sole proprietor, put your first, middle and last name.
Line 2: Enter your trade name (This is a name you use for branding and trade purposes. If there’s no separate trade name, leave it blank)
Line 3: Whomever’s details you enter in this line, make sure you give their complete details in lines 4a and 4b, especially if it’s the executor of an estate, or trustee of a trust.
Line 4: The mailing address you provide in Line 4a and 4b is crucial because it’s where the IRS will send your EIN confirmation letter (CP 575) and any official notices. If this is incorrect, you might miss important tax documents, delaying your ability to operate or comply with IRS regulations.
Line 5a and 5b: This is applicable to you if you have a physical address that’s different from the mailing address. Make sure you don’t enter a PO box number in line 5a.
Line 6: Has the provision for entering county and state where your principal business is located. The IRS uses the county and state listed here to assign your business to the correct tax jurisdiction, determine regional IRS office processing, and help with accurate tracking for state and local tax coordination (especially for payroll and employment tax responsibilities).
Even if your mailing address (Lines 4a/4b) is handled by an accountant or a registered agent, Line 6 must reflect where your business or trust is physically located.
Line 7a and 7b: Lines 7a and 7b identify the responsible party as the individual who ultimately controls, manages, or directs the entity. The IRS requires this to prevent identity fraud or shell entities, ensure proper accountability for tax obligations, and contact the right person for EIN or tax-related inquiries.
Line 8a, 8b, and 8c: If you have an LLC, you have to mark the number of members, where it was organized, and related information. If the LLC is owned by you and your spouse on a community property estate, and your LLC is taxed as a disregarded entity, you can enter 1 on line 8b.
Line 9a: Here you specify the type of business entity you have. If you run a sole proprietorship, tick that box and give your social security number. Have a corporation? Check and enter your tax form number, 1120 for a C-corp, and 1120S for an S-corp. For LLCs, what you fill out in line (a) depends on how you are taxed. By default, multi-member LLCs are treated as partnerships. You can elect for your LLC to be taxed as a C-corp or an S-corp.
If you’re a single-member LLC taxed as a disregarded entity, you would choose ‘other’ in 9a and write disregarded entity in the box.
If you’re a multi-member LLC taxed as a partnership, you would choose partnership.
Line 9b: Enter the state or country where your corporation is incorporated (if in a foreign country). This doesn’t apply to an LLC.
Line 10: In most cases, the reason for entities to apply for EIN through a Form SS-4 is to start a new business or for banking reasons. However, please check which reason applies the most to you and check the correct box.
Line 11: Enter the exact date when you began your business or acquired an existing business.
Line 12: Depending on which year you follow (calendar year, or fiscal year), enter the month you close your books and send it for audit.
Line 13: Based on your headcount planning for the next 12 months, type in the total number of employees you expect to have (existing + new) and enter the number in the ‘other’ column, if they are not agricultural or household. If you enter zero in all 3 columns of line 13, you can skip line 14.
Line 14: If you expect your tax liability to be $1,000 or less during the calendar year, you are eligible to file Form 944 annually instead of filing Form 941 quarterly. If you’re eligible for Form 944, you have to check off this box.
Line 15: Note down the date of your first payroll or put down N/A if you don’t have any employees in your entity.
Line 16: Check the type of business that resonates with yours the closest. Pick one that matches with your NAICS or SIC industry code.
Line 17: Add a bit of an additional description, providing further details on the exact line of business you are in.
Line 18: If you’re a business with an EIN already, or applying for a new EIN, you may want to check this box accordingly.
This Party Designee This is an important section to fill in if you want to authorize someone like your business lawyer, or tax preparer to answer questions about form SS-4, or receive EIN on your business’ behalf. Please note that this agent must be duly recognized and have that authority submitted to the IRS.
How to Submit Form SS-4?
Once you fill in all the information in the Form, review it and see if there are any typos, or missed out information. You have four options to submit the form to the IRS. You can fax it, mail it, file over the phone, or submit it online.
| Please note |
| Only international applicants can file by phone. Only US applicants can file it online. |
If you’re going to mail it to the IRS, send it to the following address:
Attn: EIN Ops,
Cincinnati, OH 45999
If you’re going to fax it, here’s the fax number: 855-641-6935
If you have no legal residence in the US, you fax it to 855-215-1627 (within the US), and 334-707-9471 (outside the US).
What is the deadline for filing Form SS-4?
No designated deadline for Form SS-4. Make sure you don’t file it too early (Before you begin the business), or too late (after you begin your business, just before a big business decision).
What Are the Most Common Mistakes to Avoid for Form SS-4?
- Listing the wrong responsible party
Ensure the responsible party is the individual who owns or controls the entity, not an external consultant or nominee.
- Entering an incorrect or incomplete address
Double-check both mailing and physical addresses. Ensure mail can be reliably delivered there (especially for EIN confirmation).
- Giving an invalid reason for applying
Choose from IRS-acceptable reasons: Started a new business, Hired employees, Banking purposes, Compliance with IRS withholding, etc.
- Not signing the form
The responsible party (or authorized third-party designee) must sign and date the form before submission.
- Requesting a second EIN when one already exists
Check prior records or call the IRS to verify if an EIN already exists for your entity. Use Form 147C to retrieve a lost EIN if needed.
How to Amend Form SS-4?
You cannot technically “amend” Form SS-4 after submission, but you can update or correct your business information with the IRS. To do this, you need to write a letter to the IRS on your company’s official letterhead.
The letter should include your EIN, the incorrect information, and the correct details, and must be signed by an authorized individual (such as the business owner or responsible party). Mail it to the IRS address where you originally sent your Form SS-4. The IRS will typically update your records after verifying the request.
What Should I Do If I Lose Form SS-4?
Call the IRS Business & Specialty Tax Line at 800-829-4933. Request an EIN verification letter (Form 147C). Only the business owner or authorized party can make this request. The IRS will fax or mail the letter upon identity verification.
How to Get a Replacement Form SS-4
If you’ve lost your SS-4, you can’t get the original form back, but you can call the IRS to request Form 147C, which serves as official proof of your EIN. The IRS will verify your identity and send it by fax or mail.
