Form SS-4, the application for an employer identification number (EIN), asks for two addresses. If you're fine with IRS mail going to your agent, our reading is that a registered agent's address can go on line 4, the mailing address. Line 5 is for your company's own physical address.
We read the December 2025 revision of Form SS-4 and its instructions. We searched three IRS documents for the words "registered agent": the form, the PDF instructions and the web version of the instructions. Each search returned zero matches. The word "virtual" returned zero matches too. So the IRS texts we read neither forbid nor approve an agent's address. The answer has to come from the purpose of each line.
Answers online disagree. Of the 10 results on page one of a Google search we ran on October 24, 2026, three snippets said no and three said yes. None of the 10 results came from the IRS. Below, we go through the lines one at a time with the IRS wording.
Form SS-4 asks for two addresses, and each line follows its own rule
Page 1 of Form SS-4 labels the two address lines this way:
- "4a Mailing address (room, apt., suite no. and street, or P.O. box)"
- "5a Street address (if different) (Don't enter a P.O. box.)"
Lines 4b and 5b hold the city, state and ZIP code. Both labels add "(if foreign, see instructions)."
The instructions give each line a different job. For lines 4a–4b, the first sentence reads:
"Enter the mailing address for the entity's correspondence."
For lines 5a–5b, the instructions say:
"Provide the entity's physical address only if different from its mailing address shown on lines 4a–4b. Don't enter a P.O. box number here."
Line 6 then asks for the county and state where the business is located. Its instruction reads "Enter the entity's primary physical location."
| Line on Form SS-4 | What the IRS text asks for | P.O. box | IRS wording |
|---|---|---|---|
| 4a–4b | The mailing address for the company's mail | Allowed by the label | "Enter the mailing address for the entity's correspondence." |
| 5a–5b | The company's physical address, only if different from line 4 | Not allowed | "Don't enter a P.O. box number here." |
| 6 | The county and state of the main business location | No rule stated | "Enter the entity's primary physical location." |
Can a registered agent address go on line 4, the mailing address line?
Line 4 is where the IRS sends your company's mail. The instructions add one more sentence about the line: "Generally, this address will be used on all tax returns." In our reading, nothing in the text stops you from using your agent's address here. The line asks for a mailing address, and an agent's office can receive mail.
The trade-off is where your IRS mail lands. IRS letters to your company would generally go to the agent's office. Before you choose that, ask your agent in writing two things. First, does the agent forward IRS letters? Second, to which address does it forward them? We looked at what state laws require agents to forward in can I use my registered agent address as my business address.
Line 3 offers a related option. The form lets you name a "care of" person, and the instructions explain one use:
"If the entity applying has a designated person to receive tax information, enter that individual's first name, middle initial, and last name as the "care of" person."
When line 3 is filled in, line 4 follows it. The instructions say "If line 3 is completed, enter the address for the executor, trustee, or "care of" person." The text asks for an individual's name. We found no IRS sentence that puts an agent company in the "care of" slot.
Can a registered agent address go on line 5, the street address line?
Line 5 asks for "the entity's physical address." In our reading, an agent's office is the agent's physical address. Your company doesn't operate there, so the agent's address doesn't describe where your company is. Line 6 points the same way, because it asks for "the entity's primary physical location."
Line 5 also has a condition built in. You fill it in "only if different" from the mailing address on line 4. Say your company receives mail at the same place where it operates. In that case, the instructions don't ask you for a separate line 5 address.
Some companies operate outside the United States. The line 5b label tells foreign filers to "see instructions." In our reading, an agent's U.S. office doesn't become your company's location just because you have no U.S. office of your own.
Which addresses work on each line: home, P.O. box, virtual mailbox, or foreign address
The table below sorts five common choices. Where a cell quotes the IRS, the rule is in the text. Where a cell says "our reading," we drew the answer from the purpose of the line.
| Address | Line 4 (mailing address) | Line 5 (street address) |
|---|---|---|
| Registered agent's office | Our reading: allowed, and IRS mail goes to the agent | Our reading: no, because the office is the agent's location |
| Your home | Our reading: allowed if your mail reaches you there | Our reading: yes, if the company operates from your home |
| P.O. box | Allowed by the label: "or P.O. box" | Not allowed: "Don't enter a P.O. box number here." |
| Virtual mailbox (a street address at a mail service) | Our reading: allowed as an address where you receive mail, though the IRS texts never use the word "virtual" | Our reading: no, because the company doesn't operate at the mailbox |
| Foreign address | Allowed if written in full, with the country name | The label says "(if foreign, see instructions)" |
For a foreign mailing address on line 4, the instructions set a format:
"If the entity's mailing address is outside the United States or its territories, you must enter the city, province or state, postal code, and the name of the country. Don't abbreviate the country name."
Where your business is located also decides how you apply. The IRS page for the online EIN tool lists this condition: "Your principal place of business is in the U.S. or U.S. territories." Under the cases where you can't use the tool, the same page lists "Your principal place of business is outside the U.S. If so, apply by phone, fax or mail." The SS-4 instructions add that "Only international applicants can receive an EIN by telephone."
The P.O. box rules have more detail in our guide to a P.O. box for an LLC. Home addresses on each kind of form are covered in can I use my home address as my business address. The difference between the two address types is explained in business mailing address vs business address.
Is the address on your EIN application public?
Generally, no. The privacy notice in the SS-4 instructions states: "Generally, tax returns and return information are confidential, as required by section 6103."
The law that notice cites is 26 U.S.C. § 6103. Subsection (a) begins: "Returns and return information shall be confidential…" Subsection (b)(2)(A) says return information includes "a taxpayer's identity." Subsection (b)(6) defines taxpayer identity as "the name of a person with respect to whom a return is filed, his mailing address, his taxpayer identifying number …" So the statute lists a mailing address and a taxpayer number inside the information it protects.
Confidential doesn't mean the IRS keeps the form to itself. The same SS-4 notice lists who receives the data:
"We disclose this form to the Social Security Administration (SSA) for their use in determining compliance with applicable laws. We may give this information to the Department of Justice for use in civil and/or criminal litigation, and to cities, states, the District of Columbia, and U.S. commonwealths and territories for use in administering their tax laws."
After that passage, the notice names more sharing, such as with other countries under tax treaties and with other federal and state agencies.
Tax-exempt organizations are the main exception. Under 26 U.S.C. § 6104(b), certain annual return information of exempt organizations, "together with the names and addresses of such organizations and trusts, shall be made available to the public." In our reading, a for-profit LLC or corporation doesn't fall under that rule.
Your company's address can still reach public view through other paths. State formation filings are one. We map which state slots are public in which LLC address goes on the public record and in our guide to the business address on public records. An address you give a payer on Form W-9 is another path. That payer generally prints the address on the 1099s it sends, as we explain in what address to put on a W-9.
How do you fix it if you already used your agent's address?
The SS-4 instructions name the form for later changes: "File Form 8822-B to report any subsequent changes to the entity's mailing address." The IRS page for Form 8822-B lists three kinds of change it covers: "Business mailing address. Business location. Identity of your responsible party."
On the form itself, line 6 is the "New mailing address." Line 7 is the "New business location." Your agent's address might have gone on line 4 of your SS-4. In that case, line 6 of Form 8822-B is where your new mailing address goes.
Form 8822-B also allows a "care of" address. Its instructions say: "If you receive your mail in care of a third party (such as an accountant or attorney), enter "C/O" followed by the third party's name and street address or P.O. box."
Plan for a delay. The form states: "Generally, it takes 4 to 6 weeks to process your address or responsible party change." The form also explains why the change matters:
"However, if you fail to provide the IRS with your current mailing address or the identity of your responsible party, you may not receive a notice of deficiency or a notice of demand for tax. Despite the failure to receive such notices, penalties and interest will continue to accrue on any tax deficiencies."
Telling your agent or your state about a new address doesn't update the IRS. Under 26 CFR 301.6212-2(b)(1), address information given "to a third party, such as a payor or another government agency, is not clear and concise notification of a different address" for the IRS rule on your last known address. Our step-by-step post on how to change your LLC address with the IRS covers the full process.
This post explains the text of IRS forms, IRS instructions and federal tax law. The post isn't tax or legal advice. Confirm how the rules apply to your company with a tax professional.
How an Auteur address fits line 4
We sell virtual mailboxes, so this is the seller's view. Auteur is in pre-launch, and your exact street address is assigned the day your city opens. We don't say the IRS, a bank or a platform will accept our address. Each of them may apply its own rules. We offer our address for line 4, the mailing address. We don't suggest putting a mailbox address on line 5.
An EIN for an LLC or a corporation means IRS mail arrives in the company's name. The Virtual Business Address receives mail in a business or trade name, plus individual names on the plan. The Virtual Mailing Address is for personal mail, in individual names only. Choose it only if every letter you expect comes in your own name.
Both plans photograph the envelope of every piece as it arrives, and we open and scan only when you ask, for one flat fee per piece. Henry, our AI assistant, explains each letter you ask us to open. USPS Form 1583 is required before any provider can receive mail for you. Pricing comes by email with the next steps, and our fees and limits are in our fair use policy.
If your IRS mail comes to a company name, get your Virtual Business Address. Ordering is free, there's no card, and nothing is charged today. For mail in your own name only, the Virtual Mailing Address is the plan to choose.
FAQ
Should I use my registered agent address for my EIN?
The IRS texts we read don't answer that question directly. Form SS-4 and its instructions never mention a registered agent. In our reading, an agent's address can go on line 4 if you accept that IRS mail will go to the agent. Line 5 asks for your company's own physical address, which an agent's office isn't.
Can my EIN address be different from my business address?
Yes. Form SS-4 has a mailing address on line 4 and a street address on line 5. The instructions say to provide line 5 "only if different from its mailing address shown on lines 4a–4b." So the form expects that the two can differ.
Does the online EIN application ask for the same two addresses?
The IRS pages we read don't show the online screens, so we can't describe them. Those pages say the online tool is only for a business whose principal place of business is in the U.S. or U.S. territories. A business located outside the U.S. applies by phone, fax or mail.
Can I use a P.O. box for my EIN?
On line 4, yes. The label reads "Mailing address (room, apt., suite no. and street, or P.O. box)." On line 5, no. The instructions say "Don't enter a P.O. box number here."
Can I use my home address for my EIN without making it public?
The SS-4 instructions say tax returns and return information are generally confidential under section 6103. The same notice lists government agencies that may receive the form. Your home address can still become public through other filings, such as state records or a W-9 you give a payer.
Bottom line
Form SS-4 asks for two addresses. Line 4 is where the IRS sends your company's mail, and line 5 is your company's physical address if it differs. The IRS texts never mention a registered agent. In our reading, an agent's address can fill line 4 if you accept that IRS mail goes to the agent, but an agent's office doesn't describe your company's location on line 5. The IRS treats the information as confidential under section 6103. If you already used your agent's address and want to change it, file Form 8822-B.
