Which box do I check on W-9 line 3a?

What line 3a actually asks

Line 3a asks for the U.S. federal tax classification of whoever is named on line 1 — not your industry, not your job title, and not whether you're a “business”. The form lists seven boxes: Individual/sole proprietor, C corporation, S corporation, Partnership, Trust/estate, LLC, and Other. You check exactly one.

Freelancers, independent contractors, gig workers and people renting out a property in their own name all tick “Individual/sole proprietor”. Having a business name doesn't change that; the business name simply goes on line 2.

The current revision (March 2024) changed how LLCs owned by one person answer. The October 2018 form had a box called “Individual/sole proprietor or single-member LLC”. The new form drops the LLC wording from that box and says instead that a disregarded entity checks the box for the tax classification of its owner. If a client hands you an old form, the answer is the same in practice — but read the labels carefully.

LLCs: when to tick “LLC”, and what C, S and P mean

An LLC is a state-law entity, and the IRS taxes it in one of three ways. With a single member it is disregarded by default — ignored as separate from its owner for income tax. With two or more members it is a partnership by default. Either kind can file Form 8832 to be taxed as a corporation, or Form 2553 to be taxed as an S corporation.

Only an LLC that is not disregarded ticks the “LLC” box, and it must write its classification in the space: C for C corporation, S for S corporation, P for partnership. A two-member LLC with no election is “LLC — P”. A one-member LLC that filed Form 2553 is “LLC — S”.

A disregarded single-member LLC doesn't tick “LLC” at all. It fills in the form as its owner: an individual owner ticks “Individual/sole proprietor”, a corporate owner ticks its own corporation box. If you never filed Form 8832 or 2553, your LLC has its default classification — that's the case the picker assumes when you answer “not sure”.

Line 1 or line 2: whose name goes where

Line 1 must never be blank, and the name on it has to be the one that matches the number in Part I in IRS records. A sole proprietor writes their own name on line 1 and any trade or DBA name on line 2. A disregarded LLC writes the owner's name on line 1 and the LLC's name on line 2 — the IRS says the name on line 1 should never be a disregarded entity.

Corporations, partnerships and LLCs that aren't disregarded put the entity's name as shown on its tax return on line 1. Trusts, estates and other organizations use the name on their federal tax documents, which should match the trust instrument, charter or other founding document.

The number in Part I follows line 1: the owner's SSN or EIN for a disregarded LLC, the entity's own EIN for everything else. The IRS's single-member LLC page is explicit that a disregarded LLC owned by an individual gives the owner's SSN or EIN, not the LLC's EIN.

Line 3b: who has to think about it

Line 3b was added in 2024 and most people leave it blank. It only applies if you ticked Partnership or Trust/estate, or LLC with P, and you're giving the form to a partnership, trust or estate in which you own an interest — for example, an investment partnership you're a partner in.

In that case you tick 3b if you have any foreign partners, owners or beneficiaries, directly or indirectly. The instructions add that you must tick it if one of your partners, owners or beneficiaries gave you a Form W-8 or other proof of foreign status, or gave you a W-9 with its own 3b ticked. The requester uses the answer for its Schedules K-2 and K-3 reporting.

Line 4 exemptions in brief

Individuals and sole proprietors generally leave both line 4 fields blank. Corporations are exempt from backup withholding for many payments and usually enter exempt payee code 5 — with exceptions for attorneys' fees, medical and health care payments reported on Form 1099-MISC, and payment card or third-party network payments. The form tells S corporations not to enter a code for broker transactions. Organizations exempt under section 501(a) use code 1.

The FATCA code only matters for accounts a financial institution keeps outside the United States. For a client, a landlord or a U.S. bank account, leave it blank. And if you forget an exempt payee code, the requester may still treat you as exempt when the box you ticked shows you are — the requester instructions allow that.

What the picker can't do

It can't decide your tax classification for you — that was fixed when your entity was formed or when it filed an election — and it can't check that your name and number match IRS records. Treat its answer as general information based on the current form and instructions, not tax advice. If your LLC's classification is in doubt, the acceptance letter the IRS sent after an election is the document to look for; if there's still a question, ask whoever prepares the entity's tax return.

Sources

• IRS — Form W-9 (Rev. March 2024), with its instructions
• IRS — Instructions for the Requester of Form W-9 (Rev. March 2024)
• IRS — About Form W-9 (current revision)
• IRS — Form W-9 (Rev. October 2018), the previous revision
• IRS — Limited liability company (default classification)
• IRS — Single member limited liability companies
• 26 CFR 301.7701-3 — Classification of certain business entities