What Is a Form SS-4? Definition and Use

Definition

Form SS-4 - Form SS-4 is the IRS application for an Employer Identification Number, naming the entity, its responsible party, and its federal tax classification.

SS-4 is where the entity declares its "responsible party," a natural person who controls it, listed with an SSN, an ITIN, or the word "Foreign" for non-residents who have neither. The channel depends on that person: a US applicant with an SSN can file online and receive the EIN instantly, while a non-resident submits the SS-4 by fax to the IRS and typically waits several business days for the number and the CP 575 confirmation letter, longer during peak tax season when the service center backs up.

The most common reason an SS-4 is rejected is a mismatch between the entity name on the form and the exact name on the state formation record, down to punctuation and the LLC suffix, or an incomplete responsible-party field. Another myth worth killing is that non-residents cannot get an EIN at all. The fax route has existed for precisely this case for decades and requires no SSN; the responsible party simply signs and lists "Foreign" where a US tax ID would otherwise go.

For an anonymous LLC in Wyoming, New Mexico, Delaware, or Nevada, the SS-4 is the federal counterpart to bank KYC. The IRS learns who the responsible party is, but that information is never published and does not appear on the state registry, so it leaves state-record anonymity fully intact. The form is a private federal document, not a public disclosure. Anonymousllc.co files the SS-4 as third-party designee for every formation and offers standalone EIN service at $99 for existing LLCs.

One subtlety trips up non-residents repeatedly: the responsible party must be an individual who actually controls the entity, not another company, and listing "Foreign" is legitimate only when that person genuinely has no US tax ID. Getting this field and the name match right the first time is what avoids weeks of resubmission, since a faxed rejection restarts the clock. That is why the SS-4 is checked against the filed Articles before it ever goes to the IRS.