U.S. EIN Guide: How Foreign Companies Can Get an Employer Identification Number

The Nine-Digit Key That Can Make or Break Your U.S. Expansion

When London-based fintech Wise expanded into the U.S., one of its first hurdles wasn't customers but securing an IRS Employer Identification Number (EIN) to open bank accounts and hire staff . Now, imagine you land a $500,000 U.S. client deal—you incorporate an LLC, but the bank halts you with, "You need an EIN." This isn't uncommon; in 2024, U.S. monthly business applications averaged 430,000, nearly 50% higher than 2019 . Without that nine-digit key, your U.S. operations can stall while competitors race ahead.

Why Foreign Companies Need a U.S. EIN

An Employer Identification Number (EIN)—also called a Federal Tax Identification Number—is the mechanism by which the Internal Revenue Service (IRS) tracks business tax filings, compliance, and withholding obligations . It functions like a Social Security Number for corporations, enabling a foreign company to satisfy U.S. legal, banking, payroll, licensing, and taxation requirements . Even foreign entities must secure one if engaging in U.S. business operations.

Critical Business Functions Requiring an EIN

Failing to have an EIN creates major friction, as it prevents you from legally hiring U.S. employees and reporting payroll withholdings through forms like 941 and 940. It restricts your ability to open a U.S. bank account since most financial institutions require an EIN . Additionally, without an EIN you risk delays or penalties in filing essential IRS forms such as Form 1120-F for foreign corporations and other required tax filings .

Market Urgency and Competition

The U.S. is in the throes of a business boom. In 2023, approximately 5.5 million new businesses launched—breaking all prior records. In a crowded and accelerating landscape, any administrative delay—like not having an EIN—can mean losing clients, talent, or market positioning. A foreign entrepreneur armed with an EIN can move faster, onboard seamlessly, and integrate into the U.S. economy with fewer obstacles.

Navigating the EIN Application Landscape

While U.S.-based entities can obtain an EIN immediately online using the IRS's EIN Assistant, foreign entities cannot use this portal and must instead apply through alternative methods. International applicants must complete Form SS-4 and submit it through phone, fax, or mail applications.

Application Methods for Foreign Entities

Phone applications can be made by calling IRS at +1-267-941-1099 (non toll-free), where the caller must be authorized to receive the EIN. Fax applications involve submitting Form SS-4 to appropriate fax numbers, with responses typically received within 4 business days if a return fax number is provided. Mail applications require sending Form SS-4 to "EIN International Operation, Cincinnati, OH 45999" with approximately 4 weeks processing time .

Critical Form SS-4 Requirements

When completing Form SS-4, foreign applicants must note specific requirements: Box 7 (Responsible Party) should use the name of the individual responsible for controlling the entity, and for the "SSN/ITIN" field, write "Foreign" if no U.S. tax identifier exists. Box 8a/8b requires correct entity classification (Corporation, LLC, Partnership), while Box 9a and 9b need principal business activity and NAICS code . Third-party authorization is permitted by completing the relevant section and signing authorization.

Expert Strategies and Common Pitfalls

A cross-border SaaS founder in India used a U.S. registered agent to fax their SS-4, and the IRS issued an EIN in 3 days . With their EIN in hand, they opened a U.S. bank account, launched on Stripe, and leveraged U.S. payment rails within two weeks—far faster than most competitors. Accountants and international formation services recommend preparing supporting documentation such as certificate of incorporation, proof of address, and board resolutions ahead of time .

Avoiding Application Delays

Many foreign entrepreneurs freeze at Box 7 or Box 9's NAICS classification requirements. Outsourcing preparation to a tax advisor or formation service often avoids rejections or delays. The methodology framework involves preparing entity documents, mapping business purpose to NAICS codes, completing SS-4 with "Foreign" entry for TIN, choosing fax or phone for faster processing, tracking IRS response, and integrating the EIN across U.S. business setup once received.

From EIN to Execution

Once you receive your EIN (it never expires unless business structure changes), you unlock several critical capabilities including opening U.S. corporate bank accounts or fintech accounts, registering in U.S. states through foreign qualification, applying for business licenses and permits, hiring U.S. employees and reporting payroll taxes, and filing annual returns like Form 1120-F depending on entity type. A practical challenge is coordinating state-level registrations, as even with your EIN, states may require additional qualification such as foreign LLC registration, registered agent appointment, and state withholding accounts.

Emerging Compliance Considerations

Looking ahead, emerging regulatory pressures include the Corporate Transparency Act (CTA). As of March 2025, Treasury resumed enforcement focusing specifically on foreign reporting companies—those formed outside the U.S. and doing business within. Foreign companies registered to do business in a U.S. state prior to March 26, 2025, have until April 25, 2025, to file initial beneficial ownership information reports. Ensure you maintain beneficial ownership data and compliance readiness as these requirements continue evolving.

Practical EIN Application Toolkit

Start by preparing your entity documents, such as the Certificate of Incorporation, company address, and business purpose. Next, complete Form SS-4 using the foreign applicant version—enter "Foreign" in the SSN/ITIN field and designate the responsible party correctly. Once ready, choose your application route: phone for immediate processing, fax for 4-day turnaround, or mail for 4-week processing. If faxing, include a return fax number to speed up processing. After submission, track your application and verify EIN issuance by reviewing the official IRS confirmation letter.

Integration Across Business Operations

Finally, apply your EIN across all essential areas—banking, payroll, licensing, and state registrations—to fully activate your U.S. business operations. Many foreign businesses assume EIN alone solves compliance, but in reality, EIN is just the key; you must integrate it into federal, state, payroll, and local systems for complete operational readiness.

Turning Nine Digits into Global Opportunity

Securing an EIN may feel like a small administrative step, but for foreign entrepreneurs, it's the nine-digit gateway to unlocking the U.S. market. With it, you gain access to banking, payroll, licensing, and compliance systems that allow your business to compete on equal footing with domestic players. In today's fast-moving landscape, the companies that prepare early are the ones that scale faster and capture opportunities before rivals. Think of your EIN not just as a tax ID, but as the foundation of your American expansion strategy—a simple code that can open the door to limitless growth.