In banking, a TIN is a Taxpayer Identification Number: the nine-digit number the IRS uses to track a person’s or business’s income for tax purposes. Federal law requires every bank to collect a valid TIN before opening an account, because the bank has to identify you under its Customer Identification Program and report any interest it pays you to the IRS under that number. For most individual customers, the TIN is simply your Social Security Number.
Which TIN Your Bank Is Asking For
“TIN” is an umbrella term. Which specific number satisfies your bank depends on who is opening the account.
Social Security Number
The Social Security Number is the TIN most individual customers use. The Social Security Administration issues SSNs to U.S. citizens and lawful permanent residents, and the number stays with you for life.1Social Security Administration. Types of Social Security Cards If you’re a citizen or green card holder opening a personal checking or savings account, this is the number your bank wants.
Employer Identification Number
An EIN is the business equivalent of an SSN. The IRS assigns EINs to corporations, partnerships, nonprofits, trusts, and estates so their tax obligations are tracked separately from the owners’ personal finances.2Internal Revenue Service. About Form SS-4, Application for Employer Identification Number (EIN) Any business opening a commercial bank account needs one. Irrevocable trusts and estates holding income-producing assets also need their own EIN, because the IRS treats them as separate taxable entities.
Individual Taxpayer Identification Number
If you need to file a U.S. tax return but aren’t eligible for an SSN, the IRS issues an ITIN.3Internal Revenue Service. Individual Taxpayer Identification Number (ITIN) This typically covers nonresident aliens and foreign nationals earning income in the United States. An ITIN is strictly for tax purposes: it doesn’t authorize work and doesn’t confer Social Security benefits.4Internal Revenue Service. Individual Taxpayer Identification Number (ITIN) Reminders for Tax Professionals Many banks accept an ITIN in place of an SSN for opening an account.
Adoption Taxpayer Identification Number
An ATIN is a temporary number the IRS assigns to a child placed for legal adoption when the Social Security Administration can’t yet issue an SSN.5eCFR. 26 CFR 301.6109-3 – IRS Adoption Taxpayer Identification Numbers It lets adoptive parents claim the child as a dependent while the adoption finishes.
One TIN that isn’t a banking number: the Preparer Tax Identification Number, or PTIN, is issued only to paid tax preparers so they can sign returns.6Internal Revenue Service. Frequently Asked Questions – Do I Need a PTIN You cannot use a PTIN to open an account.
Why Banks Are Required to Collect Your TIN
Two federal obligations converge at the moment you open an account.
The first is customer identification. Under the Bank Secrecy Act, as strengthened by the USA PATRIOT Act, every bank must run a Customer Identification Program. The implementing regulation requires the bank to collect your name, date of birth, address, and an identification number before opening any account. For U.S. persons, that identification number is a TIN.7eCFR. 31 CFR 1020.220 – Customer Identification Program The underlying statute gives the Treasury Secretary authority to require these procedures to guard against money laundering and terrorism financing.8Office of the Law Revision Counsel. 31 USC 5318 – Compliance, Exemptions, and Summons Authority
The second is income reporting. Any time a bank pays you $10 or more in interest during the year, it has to file a Form 1099-INT with the IRS.9Internal Revenue Service. About Form 1099-INT, Interest Income Your TIN is what links that report to your return. Without it, the IRS can’t match the income to you and the bank can’t meet its reporting obligation.
The paperwork you actually sign is usually a Form W-9, the IRS form built specifically for collecting a TIN. Signing it certifies that the number you gave is correct and that you’re a U.S. person for tax purposes.10Internal Revenue Service. About Form W-9, Request for Taxpayer Identification Number and Certification Foreign customers who aren’t U.S. persons complete a Form W-8BEN instead, which may require either a U.S. TIN or a foreign tax ID from their home country.11Internal Revenue Service. Instructions for Form W-8BEN
What Happens If You Don’t Provide a TIN
Skipping the number, or giving an incorrect one, has three real consequences:
- Backup withholding. Your bank must withhold 24 percent of your interest payments and send it to the IRS. The rule also reaches dividends, certain government payments, and other reportable income. You can recover the withheld amount when you file your return, but your money is tied up until then.12Internal Revenue Service. Topic No. 307, Backup Withholding
- A civil penalty. The IRS can charge $50 each time you fail to provide your TIN when a payer requests it, up to $100,000 per year.13Internal Revenue Service. 20.1.7 Information Return Penalties
- Account denial. Most banks simply won’t open an account without a valid TIN, because doing so puts the bank’s own Customer Identification Program compliance at risk.
Opening a Bank Account Without a Social Security Number
Not having an SSN doesn’t close the banking system to you. Many banks and credit unions accept an ITIN in place of an SSN for a checking or savings account.14Consumer Financial Protection Bureau. Can I Get a Checking Account Without a Social Security Number or Drivers License Some institutions will also work with a passport number and country of issuance, or another government-issued ID from a foreign national who has no U.S. TIN yet.
Policies vary. Credit unions and community banks tend to be more flexible than large national banks, so call ahead and confirm before you go in.
How to Get a TIN If You Need One
Applying for an EIN
Businesses apply for an EIN with Form SS-4, which asks for the entity’s legal name, mailing address, and the name and SSN or ITIN of a responsible individual.15Internal Revenue Service. Instructions for Form SS-4 (12/2025) The IRS online application is the fastest route and issues the EIN at the end of the session. It’s available Monday through Friday from 6:00 a.m. to 1:00 a.m. Eastern, Saturdays from 6:00 a.m. to 9:00 p.m., and Sundays from 6:00 p.m. to midnight.16Internal Revenue Service. Get an Employer Identification Number Fax filings take about four business days; mail filings take four to five weeks.
Applying for an ITIN
Individuals apply with Form W-7, which requires a valid federal tax reason and either a U.S. federal tax return attached to the application or a qualifying exception.17Internal Revenue Service. About Form W-7, Application for IRS Individual Taxpayer Identification Number You submit original identity documents or certified copies from the issuing agency; a valid passport is the only standalone document that satisfies both identity and foreign status.18Internal Revenue Service. Instructions for Form W-7 (Rev. December 2024) You can mail the application to the IRS Austin Service Center, apply in person at a Taxpayer Assistance Center offering ITIN services, or work with a Certifying Acceptance Agent who authenticates your documents so originals stay with you. Processing runs about seven weeks normally, and nine to eleven weeks during tax season (January 15 through April 30) or from outside the country.19Internal Revenue Service. How to Apply for an ITIN
ITINs Can Expire
Unlike SSNs and EINs, ITINs expire if they aren’t used on a federal tax return for three consecutive years. Expiration happens on December 31 after that third year.20Internal Revenue Service. How to Renew an ITIN An expired ITIN doesn’t stop a bank from reporting your interest on a 1099, but you’ll need to renew it, using the same Form W-7, before filing your own return.
Finding a TIN You’ve Lost
For a business EIN, the IRS suggests starting with the CP 575 notice mailed when the EIN was assigned, then checking with the bank that holds the business account, any state or local licensing agencies, or prior-year tax returns.21Internal Revenue Service. Employer Identification Number If those come up empty, call the IRS Business and Specialty Tax Line at 800-829-4933 (Monday through Friday, 7:00 a.m. to 7:00 p.m. local time); after identity verification, an agent will provide the EIN by phone.
For individuals, your SSN is on your Social Security card and past tax returns; a replacement card is available through the Social Security Administration. ITIN holders can find their number on the CP 565 notice sent when the ITIN was assigned, or on any previously filed Form 1040.