Sorting Out SSNs, TINs, ITINs, and EINs: Which Number Goes on the Form?

At a glance

• "TIN" is the umbrella term. Social Security numbers, EINs, and ITINs are all TINs..
• When a form asks for a "TIN," it wants the number of whoever owns the account: you, your trust, an estate, or a business.
• An "employer" identification number isn't just for employers. Trusts and estates use them too.
• A trust's number can change. A revocable trust usually uses your Social Security number while you are alive, and it needs its own EIN after you die.
• When in doubt, send the form to your attorney or accountant through a secure channel before you sign it.

If tax identification numbers confuse you, you're in good company. The rules are clear enough on paper, but the names are misleading, and the forms don't always help. Even professionals who don't apply for these numbers regularly mix them up.

Take the employer identification number, or EIN. Despite its name, it isn't limited to employers. Your trust may need one even though it has never hired anyone. That's one reason many banks, brokers, and insurance companies ask instead for a "TIN," or taxpayer identification number. They aren't using the wrong term. TIN is the broader one, and it covers whichever number belongs to the account owner.

Let's sort it out.

TIN Is the Umbrella

The IRS needs a way to identify every person and entity it deals with. "Taxpayer Identification Number" is its general term for all of these numbers. The IRS lists five:

• Social Security number (SSN). Issued by the Social Security Administration to individuals.

• Employer identification number (EIN). Used by businesses, estates, and trusts.

• Individual taxpayer identification number (ITIN). For certain people who can't get a Social Security number, such as some nonresident and resident aliens and their spouses and dependents.

• Adoption taxpayer identification number (ATIN). A temporary number for a child being adopted.

• Preparer tax identification number (PTIN). For paid tax return preparers.

For most families, only the first three matter. SSNs and ITINs identify people. EINs identify everything else.

Which Number Goes on the Form?

The best clue is a simple question: who owns the account, asset, or benefit? If you own it, use your number. If your trust owns it, use the trust's number, whatever that is right now.

Which Number Goes on the Form?

Whose account or asset is it?	Number to use	Keep in mind
Yours, in your own name	Your SSN	An ITIN if you aren’t eligible for an SSN
Your revocable trust, while you are alive	Usually your SSN	The trust is ignored for income tax while you live; no separate return
A joint revocable trust, both spouses alive	Usually one spouse’s SSN	Use the number your attorney designated, consistently
A joint trust after the first death	Survivor’s share: survivor’s SSN. Family or bypass trust: its own EIN	The split often happens at the first death, not the second
A revocable trust after the grantor dies	The trust’s new EIN	Never the decedent’s SSN
An irrevocable trust taxed to the grantor, such as many Medicaid asset protection trusts	Often the trust’s EIN; sometimes the grantor’s SSN	Check the certification of trust or ask the drafting attorney
Any other irrevocable trust	The trust’s EIN	The trust files its own Form 1041
A probate estate	The estate’s EIN	Separate from any trust’s EIN
A business with employees, a partnership, or a corporation	The business’s EIN	One EIN per entity; never shared
A sole proprietorship or single-member LLC with no employees	Often the owner’s SSN	Excise taxes, retirement plans, or a bank’s policy may still require an EIN

A general guide only. The trust document and the way the trust is taxed control, so confirm the number with your attorney or accountant before you sign.

Trusts: The Number Follows the Tax Status

While you are alive, a revocable trust is usually a "grantor trust." For income tax purposes it is ignored: its income is reported on your own return, and it typically uses your Social Security number.

Irrevocable trusts vary. Some are taxed as separate taxpayers and always need their own EIN. Others, including many Medicaid asset protection trusts, are still taxed to the grantor. Those trusts often get an EIN anyway, but the trust's income may still be reported to the grantor. Your certification of trust, or the attorney or accountant who set up the trust, can tell you which number it uses.

When the grantor dies, a revocable trust usually becomes irrevocable and a separate taxpayer, and it needs its own EIN. Getting that application right matters more than most people expect; see our article on getting the trust's EIN right after a death.

Applying for an EIN Without an SSN or ITIN

To apply online, the IRS requires the Social Security number or ITIN of the "responsible party," the person who actually controls the entity (IRS). If the person in control has neither, the choices are:

• Get an ITIN first, then apply online.

• Apply on paper. File Form SS-4 by fax or mail. Keep a copy of the signed Form SS-4. The online tool shows the assignment notice on screen. The fax and mail paths do not, and that copy is what the next institution will ask for.

Don't count on the IRS phone line if you are not an international applicant  Phone applications are only for applicants with no legal residence or principal place of business in the United States. A U.S. trustee who has neither an SSN nor an ITIN will be turned away and told to fax or mail Form SS-4.

An attorney or accountant can help as an authorized third-party designee, with your signed authorization. A designee can't stand in as the responsible party, though. That has to be the person who really controls the entity.

SSN or ITIN: What's the Difference?

A Social Security number is tied to work authorization and to Social Security benefits at retirement or disability. An ITIN is only for taxes. It lets someone who can't get a Social Security number, such as a nonresident who owns U.S. property or a business, file returns and pay tax. It does not authorize work or create Social Security benefits.

Still Confused?

Ask before you sign. Your attorney or accountant can usually identify the right number in minutes, and a wrong number on an account application can take months to untangle.

If you're not sure which number a form wants, send it to us before you complete it, with a note about what you're trying to do. Please use a secure portal or encrypted email rather than ordinary email or fax, especially once a Social Security number is on the page. We'll fill in the correct number and send it back.

Bottom Line

"TIN" is the family name; SSN, EIN, and ITIN are its members. Match the number to whoever owns the account, and remember that a trust's number can change with its tax status, most often at a death. When the form and the facts don't line up, a quick question now saves a lot of trouble later.

Sorting the confusion between SSNs,TINs, ITINs, and EINs

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If you are confused regarding taxpayer identification numbers, don't feel bad.  Although they are rather straight-forward and it is "technically" clear which you need in a particular situation, they are nonetheless confusing to lay persons, and even professionals that do not routinely apply for assignment of these numbers.  

Just the term Employer Identification Number (EIN) creates confusion, since it is not limited to just employers.  In fact, for this very reason, some financial companies. brokers, and insurance companies will not, on their forms, refer to an EIN, using instead the term Taxpayer Identification Number (TIN), when they clearly are requesting the former and not the latter.  Why?  The only explanation is that they know that your trust, for example, isn't an employer, and you will become confused that the request doesn't pertain to your trust.

There is another example of this type of practice regarding warning on tanks and tank trailers. "Flammable," right?  Well, except for the fact that there is, or at least was, technically no word, "flammable!" The correct word is "inflammable."  To avoid confusion, manufacturers use the "wrong" word rather than the "right," and for good reason- we wouldn't someone pounding, heating, or setting ablaze a tank that was labeled "inflammable," thinking incorrectly that it wouldn't burn or explode, right? In that same way, financial services companies use a more common reference Tax Identification Number rather than Employer Identification Number to "avoid" confusion. 

So let's see if we can clear any confusion.

What are Tax Identification Numbers? 

For the IRS to conduct its business, it must have an easy way to identify each individual, trust, and business or non-business entity. To do this, the IRS requires each individual and entity to have a Tax Identification Number. While most individuals use their Social Security Number (SSN) for filing taxes, most businesses and non-business entities, like trusts, must have a special tax identification number instead.

Please note that  we are referring generally to tax identification numbers.  There is a specific Taxpayer Identification Number (TIN) which the Service usually designates as (ITIN) for "Individual" Taxpayer Identification Number.   

SSN, ITIN or EIN: What’s the Difference?

There are three main categories of tax ID numbers: Social Security Numbers (SSN), Employer Identification Numbers (EIN) and Individual Taxpayer Identification Numbers (ITIN).  SSNs and ITINs are used for individuals. Generally, the ITIN is for those not eligible for an SSN, such as non-resident aliens or resident aliens not yet eligible for a social security number. 

For businesses and non-business entities, like trusts, the EIN is the most important tax identification number. Despite the name including "employer," it suits all businesses, or non-business entities such as a trust, even those with no employees. 

So one of the biggest clues what you need is "to what are you referring as the owner or beneficiary of the asset, account, or benefit?"  If you are referring to a trust, use the EIN for the trust.  

The trust usually uses your social security number if you are the Settlor/Grantor of a revocable trust.  When the trust qualifies as a "Grantor Trust,"  it is a disregarded entity which uses the Grantor's social security number.   

If the Trust is irrevocable, the trust may have a separate EIN, so you will need to either: 1) refer to the Certificate of Trust which will identify the EIN; or, 2) ask your attorney or accountant that obtained the EIN. Most attorneys make clear on the Certificate Trust is the irrevocable trust is treated by the IRS as a separate entity requiring an EIN, and typically will obtain one for the trust. 

Tax ID Numbers for Businesses

Most businesses require a special tax identification number for their filings with the IRS. Many other legal documents for businesses, including loan applications, bank account applications and permit applications, also require a tax identification number. Therefore, one of the first actions to take after setting up your business is to apply for an EIN.

Are There Exceptions?

There are cases in which business owners can use their own social security number rather than an EIN for filing taxes for their business. The two exceptions are sole proprietorships and certain LLCs, as long as the LLC does not have any employees. In these cases, the business owner can use his or her SSN in place of the EIN. However, even sole proprietors might need a EIN under certain circumstances, such as for excise tax returns or pension filings.

You have your choice of business structure, which might impact what type of Tax Identification Number you need. Start your tax ID application to receive your EIN number by filling out the form here. Alternatively, complete a sole proprietorship application and use your social security number instead. Our support team is available 24/7 to assist you with any questions you might have about filing these applications.

Do I Need an ITIN or Social Security Number to Get an EIN?

There are ways to get an EIN for your company without having either a Social Security number or an ITIN, but in most cases, you do use those other tax identifiers in your application. That’s because the IRS does require the person who takes responsibility for the registration to have one of these. If you do not have either identifier, you have two options.

• File for either a SSN or ITIN before applying for an EIN so that you can be listed as the point of contact for the company.
• Engage an accountant or lawyer willing to act as that contact for the company and submit their information so they can receive paper records regarding your EIN.

What Are the Differences Between a SSN and an ITIN?

The main difference is that the Social Security number is for those who are eligible for Social Security benefits, either at retirement or in the event of a disability. For residents of the U.S. and non-residents who own businesses in the country, the ITIN provides and individual tax identification option outside of Social Security. This is an important avenue for those who do not qualify for a Social Security number.

Can I Use a Tax ID Number for More Than One Business?

Generally, no. If your business needs its own EIN for any reason, you need to use a unique one that is just for that entity. Entrepreneurs with multiple companies they own as the sole owner, either through sole proprietorship or a single-member LLC, might have the option of lumping all their business taxes under one tax return by using their Social Security numbers and filing with Schedule C. Even then, if any of those businesses hire employees or seek bank loans, they will need their own EIN, and they will not be able to share.

Still Confused?

Your attorney or accountant will usually help you quickly identify and locate the correct number.  Rather than create additional work later, we suggest that clients fax or email the forms they are completing with an indication what they are trying to accomplish.   We usually will simply insert the correct "number" and send it back for completion.  Regardless, if you are confused, ask for help!

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