You do not need an ITIN to open a Mercury business account. Mercury's FAQ lists the requirements: the company's formation documents, its IRS-issued EIN document, and a government ID such as a passport for at least one person with operating control and any owner of 25 percent or more, with a US or international address for the principal place of business (read September 14, 2026). The ITIN enters when the business outgrows the fintech: a national bank that opens in person and identifies the owner by taxpayer number, the credit cards issued on the owner's file, and any US return in the owner's name.
Does Mercury require an ITIN?
No. Mercury's FAQ, read September 14, 2026, answers the question what do I need to apply for an account with three items: your company's official formation documents, your IRS-issued EIN document, and a government ID, for example a passport or a US government identification document, for at least one person with operating control and for any owner with at least 25 percent of the company. Customers must be formed in the United States or a US territory, with existing or planned US operations and a US or international address for the principal place of business. Nothing on that list is an SSN or an ITIN; the FAQ adds that a Social Security number, where a person has one, is used solely to verify identity, with no credit check. That is why a non-US founder can open a Mercury account from anywhere in an afternoon.
Mercury is not itself a bank. Its FAQ says it works with two FDIC-insured banks, Choice Financial Group and Column N.A., and that deposits are insured up to $5 million through those partners and their sweep networks. Richard, whose account sat with Choice Financial behind Mercury, learned what that meant when he asked for credit.
And Relay?
Relay describes itself on its own site as a financial technology company, not an FDIC-insured bank, with banking services provided by Thread Bank, Member FDIC. Its plans start at $0 a month, and it says deposits qualify for up to $3,000,000 in FDIC coverage through Thread Bank's sweep programme (relayfi.com, read September 14, 2026). The page that says who can open an account and what identification it takes was not at the address we tried that day, so we quote nothing on eligibility; read it when you apply. The structure is Mercury's: a US company, its EIN, an owner identified by a government document, deposits at a partner bank. The questions that matter to you are the same too.
What the fintech account gives you
- A US business account opened online, on the company's EIN and your passport, usually within days.
- US account and routing numbers, so US customers and platforms can pay the company.
- Debit cards, bill pay, invoicing and the software conveniences a bank branch does not offer.
- A place to land Stripe, Shopify and marketplace payouts while the rest of the base is built.
What it cannot give you
| You want | Fintech account | Account at a national bank, opened in person |
|---|---|---|
| A credit file in your name | No. Nothing is reported for you | Yes, once cards are issued on the account and the history |
| Credit that grows with the business | Limited to what you hold, in Richard's words | Cards and lines decided on your file and relationship |
| Statements other institutions trust | Discounted, in the Latvia founder's words | Accepted by landlords, issuers and lenders |
| A banker who knows you | No branch, no banker | Yes, and it shows when a decision is close |
| Rewards on US spend | Rarely; Devan earned none on five figures a month | Points and cash back on cards issued on the file |
| Identification of the owner by taxpayer number | Not required | Expected: passport and ITIN |
Where the ITIN enters
At the moment the fintech stops being enough. The federal customer identification rule, 31 CFR 1020.220, lets a bank identify a non-US person by taxpayer number, passport number or another government document; the national banks our clients use expect the passport and the taxpayer number, and open in person. Card issuers file the owner's history under the same number. Any US return in your name carries it, and for a foreign-owned single-member LLC the Form 5472 instructions ask for it. The LLC owner's guide covers that filing.
Devan ran five figures a month of advertising through Mercury and earned nothing back until the Amex Gold. Richard moved a multi-owner Wyoming LLC from fintech credit to six figures at Chase. Both journeys ran through the same first step.
Start with the fintech, do not stop there
Our advice is not to avoid Mercury or Relay. Open the account, land the payouts, pay the bills. Then get the number, put the company's documents in a shape a banker accepts, and open the accounts in Miami in person; keep the fintech for what it is good at. The comparison guide goes deeper on the trade, and the Mercury closure guide explains what to do when a fintech decides it is done with you, which happens.
How to get the number
Form W-7 with a valid passport, filed with the return that needs it or under one of the five exceptions in the instructions. The IRS allows 7 weeks, 9 to 11 in peak season or from abroad, and charges nothing. Through a Certifying Acceptance Agent the passport is verified in a live video session and certified. Our fee is $399, refundable until we file.