I-9 vs W-4 in 2026: Who Fills Out Which Form (and the $28,619 Penalty If You Get It Wrong)

Two single-page forms sit in the new-hire packet of every W-2 job in the United States, and almost every new employee fills them out within minutes of each other. The I-9 goes first, often before the offer paperwork is even fully signed. The W-4 follows the same morning, sometimes on the same clipboard. They look almost interchangeable: short, federally branded, asking for your name and a number, signed at the bottom. They are doing entirely different jobs for entirely different agencies, and only one of them can land your employer with a five-figure fine if it is wrong.

The I-9 (Employment Eligibility Verification) is the document your employer uses to verify, on penalty of federal fine, that you are legally authorized to work in the United States. It exists because of the Immigration Reform and Control Act of 1986 (IRCA), codified at 8 U.S.C. §1324a, and it is jointly administered by U.S. Citizenship and Immigration Services (USCIS) and U.S. Immigration and Customs Enforcement (ICE).^[1] It has nothing to do with the IRS or your taxes — it is an immigration document that happens to be triggered at hire.

The W-4 (Employee's Withholding Certificate) is the instruction you give your employer about how much federal income tax to take out of each paycheck. It exists because of the Current Tax Payment Act of 1943 — the statute that created paycheck withholding — and is codified at Internal Revenue Code §3402.^[2] Your employer uses it together with the IRS percentage-method tables in Publication 15-T to compute the federal-tax line on every pay stub.^[3]

One verifies that you are allowed to work. The other tells your employer how to compute your tax. If you only remember one line: I-9 for DHS, W-4 for IRS. Everything else in this article flows from that distinction.

What the I-9 and W-4 actually are — the one-paragraph version

Congress passed IRCA in 1986 after a decade of immigration-reform negotiation. The compromise: Congress would offer an amnesty path for certain unauthorized workers already in the country, but in exchange would impose criminal and civil penalties on employers who hired unauthorized workers going forward. To make the prohibition enforceable, IRCA required every employer to verify, at the moment of hire, that each new employee was a U.S. citizen, lawful permanent resident, or otherwise authorized to work. The mechanism Congress chose was a paper form — Form I-9 — completed jointly by the employee and the employer, retained in the employer's files, and produced on demand for ICE inspection.^[1]

The W-4 has a longer history. Federal income-tax withholding from wages was introduced in 1943 during World War II to fund war spending faster than annual tax returns would allow. The W-4 is the form an employee uses to tell the employer how much to withhold — accounting for filing status, dependents, second jobs, deductions, credits, and other-income adjustments. It has no immigration purpose and never has. Its job is to make sure the federal income tax line on your W-2 at year-end is close to your actual liability, so you do not face a surprise tax bill or a wasteful refund.^[2]

The reason the two forms sit together in the hiring packet is convenience, not legal symmetry. The new-hire paperwork moment is the only time HR has the employee captive long enough to collect every required document at once — the I-9, the W-4, the state withholding form, the direct-deposit form, the benefits enrollment, and the company handbook acknowledgment. From the employee's side they all feel like one stack. From the agency-enforcement side they are governed by four different statutes and four different inspection regimes.

Who fills out which form (and when)

The two forms sit on opposite sides of a simple rule. The I-9 is universal: every W-2 employee hired in the United States since November 6, 1986 has had to complete one, regardless of citizenship, regardless of salary, regardless of full-time or part-time status, and regardless of whether the employer is a Fortune 500 corporation or a household hiring a single nanny.^[4] The W-4 is also universal for W-2 employees, but it has cousins for non-wage situations (the W-4P for pensions, the W-4R for retirement distributions, the W-9 for independent contractors).

The I-9 is required when

• You are being hired as a W-2 employee. Anyone receiving paid labor on U.S. soil for a U.S. employer is in scope, including part-time, seasonal, temporary, and on-call workers. Even a single day of paid work triggers the requirement.
• You return to the same employer after a break exceeding the rehire window. If you are rehired within three years of the date on your original I-9, the employer may complete only Supplement B (formerly Section 3) to update your information instead of starting a new form. Past three years, a new I-9 is required.
• Your work authorization document on file is about to expire. The employer must reverify in Supplement B before the expiration date of the document you presented in Section 2 (with two exceptions: U.S. passports and Permanent Resident Cards, even when those have an "expiration" date, do not trigger reverification).
• You are completing the alternative remote inspection procedure. Available only to employers enrolled in E-Verify in good standing, this procedure allows Section 2 review of digital copies via live video — but the I-9 is still completed within the three-business-day window.^[5]

The W-4 is required when

• You are being hired as a W-2 employee. Required by IRC §3402(f)(2)(A) "on or before the first day on which the employee is employed." Without a valid W-4 the employer must withhold as "single, no adjustments" by default.
• You experience a major life event. Marriage, divorce, the birth or adoption of a child, a spouse starting or stopping work, taking a second job, a large change in itemized deductions, large non-wage income — any of these can shift your withholding needs enough that the IRS recommends re-running the Tax Withholding Estimator.^[6]
• You receive a pension, annuity, or eligible rollover distribution. A Form W-4P applies to periodic pension and annuity payments; a Form W-4R applies to nonperiodic distributions and eligible rollover distributions from a 401(k) or IRA.
• The IRS issues a "lock-in letter." Rare, but if your withholding has been chronically too low, the IRS can issue Letter 2800C to your employer setting a maximum number of allowances. Your employer must follow the lock-in until released.

Filling out the I-9 in 2026 — Section 1, the employee's part

The Form I-9 you complete in 2026 has an edition date of 01/20/2025 and is valid through 05/31/2027. USCIS also reprinted the prior 08/01/2023 edition with the 05/31/2027 expiration; that reprint remains acceptable. The earlier 08/01/2023 printing that shows a 07/31/2026 expiration becomes unusable on August 1, 2026 — every electronic I-9 platform must be updated by then.^[8]

Section 1 is the employee's own attestation under penalty of perjury that you are authorized to work. It must be completed no later than the first day of paid employment — the same day you start earning a paycheck. Most employers ask new hires to complete it during onboarding the day before, which is allowed; what is not allowed is completing it after the first day of paid work.

The four boxes you check

Below the personal-information fields, Section 1 asks you to attest to one of four work-authorization categories. Check exactly one:

1. U.S. citizen. Born in the United States, in U.S. territories, or naturalized.
2. Noncitizen national of the United States. A narrow category — primarily people born in American Samoa and Swains Island. Distinct from citizenship.
3. Lawful permanent resident (LPR). Green Card holders. Section 1 asks for the USCIS or Alien Registration Number (A-Number) from the Permanent Resident Card.
4. Noncitizen authorized to work until a specified date. Anyone with temporary work authorization — H-1B visa holders, F-1 students on OPT, L-1 transferees, asylees and refugees, TPS recipients, DACA recipients, and many others. Section 1 asks for the expiration date and the A-Number, USCIS Number, or Foreign Passport Number, depending on which document type you will present in Section 2.

The 01/20/2025 edition includes a checkbox question for whether a "preparer or translator" assisted with completion (and a separate Supplement A if so), and asks for your email and telephone number — both optional fields, but if you provide them they may be used by E-Verify to send you Case Status updates and Tentative Nonconfirmation notices.

Common Section 1 mistakes

• Filling in the wrong A-Number or USCIS Number. The A-Number on a Permanent Resident Card is 8 or 9 digits and begins with the letter "A." The USCIS Number on a Form I-766 (EAD) is the same 8 or 9 digits without the letter. The two are interchangeable for purposes of the form, but mismatch with what you write in Section 2 creates a Tentative Nonconfirmation in E-Verify.
• Forgetting to date Section 1. The form is invalid without the date you signed it. Even one day late is a substantive violation under the March 2026 ICE rulebook.
• Filling out Section 1 before being hired. Section 1 may be completed any time after the employee accepts the offer, but completing it before a job is even offered is the textbook fingerprint of unlawful pre-screening — an anti-discrimination violation under 8 U.S.C. §1324b.

The I-9 Section 2 — the employer's part (and the documents you bring)

Section 2 is completed by the employer or an authorized representative within three business days of the employee's first day of paid work. The employer reviews documents the employee chooses to present, records the document title, issuing authority, document number, and expiration date, and signs an attestation that the documents appeared genuine and to relate to the person who presented them.

This is where the most consequential design choice of the I-9 lives: the employee chooses the documents, not the employer. Demanding a specific document is "document abuse" — a separate violation prosecuted by the Department of Justice's Immigrant and Employee Rights Section (IER) and carrying its own penalty schedule up to $5,724 per worker plus back pay, regardless of whether the employee was harmed.^[9]

The Lists of Acceptable Documents

The Lists are printed on the last page of Form I-9 and updated by USCIS as new documents enter or leave the menu. As of June 2026, the structure is:

The number of documents required is small: one List A, OR one List B plus one List C. An employer asking for more than that minimum — say, demanding both a Social Security card AND a passport — is "over-documentation," a form of document abuse.

How Section 2 is reviewed

The employer must examine the original documents in person, or via the alternative remote inspection procedure (if enrolled in E-Verify in good standing). For in-person review, photocopies, scans, and faxes of documents are not acceptable as the originals shown to the employer — although the employer may make and retain photocopies for the I-9 file once originals have been reviewed.

For the alternative remote procedure codified at 8 CFR §274a.2(b)(1)(vi) and effective August 1, 2023, the employer-side reviewer examines copies of documents transmitted electronically and then conducts a live video interaction with the employee to verify that the same documents are in the employee's possession.^[5] This procedure is available only to employers enrolled in E-Verify and only for new I-9 completions while enrolled — it cannot be used to remediate a missing or late I-9 from before enrollment.

Filling out the 2026 W-4 — the new five-page version, step by step

The W-4 you fill out in 2026 was finalized by the IRS in December 2025 to implement the One Big Beautiful Bill Act (OBBBA, Pub. L. 119-21), signed July 4, 2025.^[11] The form is now five pages — Step 3 reflects the new $2,200 per-qualifying-child Child Tax Credit, and the Step 4(b) Deductions Worksheet expanded to 15 lines to accommodate OBBBA's new above-the-line deductions. Most people fill out only Step 1 (personal information and filing status) and Step 5 (sign); the worksheets on pages 3-5 are only needed when you have specific complications.

Step 1 — Personal information and filing status

Name, address, Social Security Number, and the filing status you will use on your 1040: Single or Married filing separately (MFS); Married filing jointly (MFJ) or Qualifying surviving spouse (QSS); Head of household (HoH). The filing status drives which withholding table the employer pulls from Publication 15-T. Get it wrong and your withholding is wrong from the first paycheck.

Step 2 — Multiple jobs or spouse works

The hardest step on the form and the one that produces the most surprise April tax bills. The withholding tables in Publication 15-T assume the income on this paystub is your only taxable income. If you have a second job or your spouse works, the standard deduction is effectively claimed twice across the two paychecks, leaving total withholding too low.

You have three options:

1. 2(a) — Use the IRS Tax Withholding Estimator at irs.gov. Most accurate when you have multiple jobs, irregular pay, or significant non-wage income.
2. 2(b) — Use the Multiple Jobs Worksheet on page 3 of the form. Reasonable accuracy if the two paychecks are roughly comparable.
3. 2(c) — Check the box if you have exactly two jobs (or you and your spouse have one job each) and the lower-paying job pays at least half of the higher-paying job. Easiest but least accurate when pay is uneven.

Step 3 — Claim dependents and tax credits

This is where the 2026 OBBBA change shows up most visibly. The Child Tax Credit was raised from $2,000 to $2,200 per qualifying child, with inflation indexing starting in 2026.^[12] The 2026 W-4 labels Step 3 lines (a) and (b) explicitly:

• Line 3(a) — number of qualifying children under age 17 × $2,200.
• Line 3(b) — other credits you expect, including the $500 Credit for Other Dependents (qualifying relatives, college-age children).

The credits phase out above $200,000 (single) / $400,000 (MFJ) of modified adjusted gross income. If your wages put you in the phase-out, complete the Step 3 worksheet instead of just multiplying children × $2,200.

Step 4 — Optional adjustments

• 4(a) — Other income. The annual amount of taxable income you expect from sources where tax is not withheld — interest, dividends, rental income, side-gig income. This causes extra federal tax to be withheld from each paycheck to cover the off-paystub income.
• 4(b) — Deductions. If you expect itemized deductions or above-the-line adjustments larger than the standard deduction, use the Deductions Worksheet on page 4. The worksheet is now 15 lines on its own page — substantially expanded for 2026 to incorporate OBBBA's new deductions:
  • Qualified tips (up to $25,000) for employees in customarily tipped occupations, if total income is under $150,000 (single) / $300,000 (MFJ).^[13]
  • Qualified overtime pay (up to $12,500 single / $25,000 MFJ).
  • Senior bonus deduction ($6,000 for taxpayers age 65+, phase-out begins at $75K single / $150K MFJ).
  • Personal auto-loan interest (up to $10,000 for qualifying U.S.-assembled vehicles purchased 2025–2028 under OBBBA §70402).
• 4(c) — Extra withholding. A flat dollar amount per pay period that the employer takes in addition to the calculated withholding. Useful when you want to cover a one-shot tax event — for example, a stock sale that will produce capital gains tax — through paychecks rather than write the IRS a check in April.

The exempt-from-withholding option also changed. Through 2025 you wrote the word "Exempt" in the space below Step 4(c). In 2026 there is a dedicated checkbox after Step 4(c). To claim exemption you must have had no federal tax liability last year and expect none this year — both conditions strictly required by Treas. Reg. §31.3402(n)-1.

Step 5 — Sign

Required. An unsigned W-4 is invalid; the employer must default to "single, no adjustments" until you correct it.

The penalty schedules: why a wrong I-9 costs more than a wrong W-4

The two forms sit in the same hiring packet but the consequences of getting them wrong diverge dramatically. The W-4 has effectively no employee-side penalty — at worst you over-withhold (and reclaim the difference on your tax return) or under-withhold (and pay the difference at filing, plus possibly an estimated-tax penalty under IRC §6654 if the shortfall is large). The employer is on the hook under IRC §3403 if they fail to follow the W-4 you submitted, but the IRS rarely pursues these.

The I-9 is a different universe. Penalties are tiered by violation type, paid by the employer, and inflation-adjusted annually under the Federal Civil Penalties Inflation Adjustment Act Improvements Act of 2015. The Federal Register publishes the new amounts every January.^[14] The 2026 figures, set by the January 2, 2025 adjustment and confirmed by ICE's March 16, 2026 fact-sheet revision, are:

The fines aggregate. In an ICE audit, an employer with 150 employees and a typical defect rate of 25% on legacy I-9s would face fines on roughly 38 forms; at the low end of the substantive band that is $10,944 ($288 × 38), at the midpoint $59,755 ($1,572 × 38), at the high end $108,718 ($2,861 × 38). For a 1,000-employee company at the same defect rate, the math reaches the seven-figure range. ICE generally aims for the mid-tier band unless aggravating factors apply.

What changed in March 2026

The ICE fact-sheet revision dated March 16, 2026 rewrote significant portions of the 1997 "Virtue Memorandum," which had governed the agency's substantive-vs-technical distinction for nearly 30 years.^[10] Under the old framework, many common defects — missing employee email, an unsigned Section 1, a Section 2 completed by an unauthorized representative — were technical and eligible for a 10-day cure period before a fine was assessed. The new framework reclassified more than ten such categories as substantive, meaning the fine is immediate and the cure period vanishes. Practitioners reporting on the change emphasize three particularly costly reclassifications:

• Late Section 2. Previously sometimes treated as technical if cured promptly; now substantive on day one.
• Missing Section 1 attestation date. Previously technical; now substantive.
• Section 2 completed by a non-authorized representative. Previously cure-eligible; now substantive on day one.

The practical lesson for employers and employees: errors that used to be footnotes are now headline-grade fines, and the highest-volume source of those errors is rushed Section 2 review on the third business day after hire. The cleanest mitigation is to budget time on day one of every new hire for proper I-9 completion, and to enroll in E-Verify if you can meet the alternative remote inspection eligibility requirements.

E-Verify and the alternative remote inspection procedure

E-Verify is a free, web-based system administered by USCIS that compares the information an employee provides on the I-9 against records held by the Social Security Administration and the Department of Homeland Security. It returns one of three results for each case: Employment Authorized, Tentative Nonconfirmation (the employee gets eight federal working days to contest at SSA or DHS), or Final Nonconfirmation.^[15]

Enrollment is voluntary for most private employers but mandatory for:

• Federal contractors whose contracts include the FAR clause 52.222-54 — generally contracts worth more than $150,000 and longer than 120 days, plus all subcontracts above $3,500 that involve covered work.
• Eight state-mandate jurisdictions as of 2026 — Alabama, Arizona, Georgia, Mississippi, North Carolina, South Carolina, Tennessee, and Utah — generally require all or most employers in the state to enroll. Several additional states (including Florida and Texas) have industry- or threshold-based mandates that may apply.
• Employers in any state who hire foreign nationals on STEM OPT extensions — the F-1 STEM OPT 24-month extension requires the sponsoring employer to be enrolled.

The alternative remote inspection procedure

Published in the Federal Register on July 25, 2023 and effective August 1, 2023, the alternative procedure at 8 CFR §274a.2(b)(1)(vi) allows certain E-Verify employers to conduct Section 2 document review via live video instead of physical, in-person inspection. Requirements: the employer must be enrolled in E-Verify in good standing, must consistently use the procedure for all employees at a given hiring site (or for all remote-hire employees, with in-person review for on-site hires), and must retain copies of all documents reviewed.^[5] The procedure has substantially reduced the practical pain of hiring fully remote employees who live more than a reasonable distance from any company office.

Three case studies — how this plays out in practice

Case 1 — Aisha, U.S. citizen, first job at age 22

Aisha graduated from a state university in May 2026 and accepted a $72,000 marketing analyst role starting June 22 at a 280-person ad agency in Chicago. HR sent her digital copies of the I-9, W-4, and direct-deposit forms to complete in the candidate portal three days before her start date.

Section 1 of the I-9 took Aisha seven minutes: she checked Box 1 (U.S. citizen), entered her name, address, date of birth, SSN, signature, and date. On her first day she brought her U.S. passport (a single List A document is sufficient on its own); the HR generalist reviewed the passport, recorded the document title, issuing authority, document number, and expiration date in Section 2, signed and dated the attestation, and made a photocopy for the file. Total elapsed time from her first day's clock-in to a complete I-9 in the file: about 35 minutes.

On the W-4, Aisha was single, no dependents, no second job, no large non-wage income. She filled out Steps 1 and 5 only, leaving Steps 2-4 blank, and checked the appropriate filing status box (Single). Her employer used the Publication 15-T percentage-method tables for "Single, Step 2 box not checked" to compute her federal withholding at $456 every two weeks against gross pay of $2,769. Through year-end, she was withheld approximately $11,856 of federal income tax. When she filed her 2026 return in March 2027, her actual tax came in at $11,604, producing a $252 refund — well within the IRS "land within ~$500" rule of thumb.

Case 2 — Diego, H-1B visa holder transferring employers

Diego is a software engineer originally from Mexico, in the United States on an H-1B visa originally sponsored by his previous employer. He accepted a new role with a tech company in Austin in May 2026 that took over his H-1B sponsorship via Form I-129 amendment. The new employer is enrolled in E-Verify.

For Section 1 Diego checked Box 4 ("Noncitizen authorized to work until a specified date"), entered the expiration date from his current I-94 (which controls his work authorization, not the H-1B approval notice date), and entered his Foreign Passport Number with the I-94 number. On the first day he presented his Mexican passport with a current I-94 endorsement — a single List A document under the I-9 Lists. The HR director, also acting as the company's E-Verify case originator, completed Section 2 within an hour and initiated the E-Verify case the same day.

E-Verify returned a Tentative Nonconfirmation (TNC) because his I-94 record had a one-character SSN mismatch in the SSA database — a known data-feed glitch when employer changes occur close in time to consular processing. Diego received the SSA's TNC notice, made an appointment at the local SSA office two days later, brought his passport and I-94, and SSA corrected the record. Within a week E-Verify updated to "Employment Authorized" and the case was closed cleanly. Total disruption to Diego: one half-day of PTO for the SSA visit. Penalty exposure to the employer: zero, because the procedure was followed.

On the W-4, Diego filed as MFJ with two qualifying children. He checked Step 2(c) because his spouse also works, claimed two children × $2,200 = $4,400 on Step 3(a), and entered $0 on Step 4. His employer pulled the appropriate Publication 15-T tables for MFJ with Step 2 box checked, producing biweekly federal withholding of $812 on gross pay of $5,769.

Case 3 — Maria, lawful permanent resident rehired by a former employer after four years

Maria is a 41-year-old hospital pharmacist in Phoenix who left her hospital employer in 2022 to take a remote pharmaceutical-industry job, then returned to the same hospital in June 2026. Because the rehire is past the three-year rehire window of her original I-9, the hospital had to start a fresh I-9, not just complete Supplement B on the old one.

For Section 1 she checked Box 3 ("Lawful permanent resident") and entered her A-Number from her current Permanent Resident Card. For Section 2 she presented her current PRC, a List A document. Because PRCs are List A and not subject to reverification (regardless of any expiration date on the card itself), no Supplement B reverification will ever be needed.

The hospital's HR onboarding coordinator, who handles roughly 14 new hires per month and is the E-Verify case originator, completed Section 2 the same morning. Total time from clock-in to a complete I-9 in the file: 28 minutes. E-Verify returned "Employment Authorized" within four minutes.

On the W-4 Maria filed as Head of Household (her divorce was finalized in 2024 and her two children live with her primarily) with two qualifying children × $2,200 = $4,400 on Step 3(a). She added $500 on Step 3(b) for her aging mother who lives with her as a qualifying relative. She entered $7,200 on Step 4(b) for the additional itemized deductions she expects (state income tax, charitable contributions, mortgage interest above the standard deduction). The hospital's payroll system computed her biweekly federal withholding at $584 on gross of $4,167.

Eight mistakes that cost real money

1. Late Section 2 on the I-9. The single most common substantive violation. The three-business-day window is hard. Calendar it into the new-hire process; do not let it slip.
2. Demanding specific documents. Asking a new hire for "your Social Security card AND a driver's license" when a single U.S. passport (List A) would suffice. The employee chooses; the employer reviews what is presented.
3. Photocopying documents but not returning the originals on the same day. Originals belong to the employee. The employer may make copies for the file but must return originals immediately after Section 2 review.
4. Failing to reverify expiring work authorization. When a List A or List C document with an expiration date is on file (other than U.S. passports and PRCs), the employer must complete Supplement B before the expiration. Skipping reverification is a substantive violation and authorizes ICE to assume the employee is no longer authorized.
5. Forgetting Step 2 of the W-4 when both spouses work. A dual-earner couple, each making $80,000, who both file MFJ without checking Step 2(c), will be under-withheld by roughly $4,000–$6,000 annually because each employer treats the other paycheck as if it doesn't exist. The fix is mechanical — check 2(c), or use 2(a)'s estimator — but the April surprise is real every year for first-time dual earners.
6. Confusing the W-4 with the W-9. The W-9 is for independent contractors; the W-4 is for W-2 employees. Filing the wrong one means either no federal withholding for an employee who needed it, or no 1099 reporting for a contractor.
7. Filing exemption on the W-4 without meeting both conditions. You must have had no federal tax liability last year and expect none this year. Filing exempt to avoid withholding when you actually owe creates an estimated-tax penalty exposure and, in pattern cases, a $1,180 frivolous-return penalty under IRC §6702.
8. Forgetting to update the W-4 after a life event. Marriage, divorce, a new child, a spouse starting a new job, a major change in non-wage income — any of these can shift the withholding picture by thousands. The IRS Tax Withholding Estimator is free, takes about 10 minutes, and is the single highest-leverage tax-planning tool the agency publishes.

State equivalents and special-case scenarios

The I-9 has no state-level counterpart — work authorization is a federal-immigration question. Some states layer on additional documentation requirements (notably E-Verify-mandate states, where the state effectively adds E-Verify as a parallel verification on top of the federal I-9), but no state issues its own version of the I-9 itself.

The W-4 has 41 state-level cousins, because 41 U.S. states (plus D.C.) levy an individual income tax that requires employer withholding. The state form names vary: California (DE 4), New York (IT-2104), Illinois (IL-W-4), Massachusetts (M-4), Texas (none — no state income tax), Florida (none), etc. Filling out the federal W-4 does not automatically populate the state form; new hires in income-tax states should expect a separate state withholding form in the same hiring packet.^[16]

Three special-case scenarios worth knowing

• Remote employees who never visit the worksite. Use the alternative remote inspection procedure if you are enrolled in E-Verify; otherwise, designate an authorized representative — generally a notary, a contracted vendor, or even a trusted family friend — to perform Section 2 in person on your behalf. The authorized representative completes Section 2 in their own name and the employer remains liable for the form's accuracy.
• Seasonal and on-call employees. Each separate period of paid employment generally requires its own I-9 unless the breaks are short enough to count as continuing employment under 8 CFR §274a.2(b)(1)(viii). The standard test: 30 days or less is treated as a break in employment but not a termination; longer than 30 days may or may not require a new I-9 depending on context.
• Workers being transferred from an acquired company in an M&A transaction. Under 8 CFR §274a.2(b)(1)(viii)(A)(7), the acquiring company may either accept the predecessor's I-9s (taking on the associated retention obligations and any latent defects) or treat the acquired workforce as new hires and complete fresh I-9s. The choice has material due-diligence implications and should be made during the deal-structuring phase, not after closing.

When you might fill out both, plus the W-9 cousin

The most common dual-form situation is the moment of original hire: every new W-2 employee fills out both the I-9 and the W-4 within the same hiring packet, on the same day, often within minutes of each other. The I-9 then sits in a permanent personnel-records file; the W-4 sits in the payroll system and is updated whenever life events occur. The two forms diverge from that moment on — the I-9 may be touched again only on reverification or termination; the W-4 may be touched several times across your tenure with a single employer.

The other dual-form situation is the rehire: if you return to the same employer within three years, the employer may complete only Supplement B on your old I-9 instead of starting a new one, but a new W-4 is required (and almost always recommended, because so many of the tax-related life variables shift over a multi-year absence).

The W-9 is the closest cousin to the W-4 in form but not in function. Independent contractors give a payer a W-9; the payer uses it to file the year-end 1099 reporting form. Contractors do not complete an I-9 and do not complete a W-4. The form you receive at hire is the highest-information single signal about how the IRS and DHS will view your relationship to the payer. See our companion piece W-9 vs W-4 in 2026 for the contractor-side walkthrough.^[17]

Action checklist — what to do this week

1. Pull out your most recent I-9 — if you have one. If you are currently employed and your employer is participating in an ICE audit (or could be), confirming that your I-9 was completed correctly is worth the five minutes. Look for Section 1 date filled in, Section 2 completed within three business days of your start date, and the documents listed match what you actually presented.
2. If you are a current employee, refresh your W-4 if any of the following has changed since you last filed: marital status; number of children or dependents; spouse's employment status; second job; large non-wage income; large change in itemized deductions; eligibility for any new OBBBA deduction (qualified tips, qualified overtime, $6,000 senior bonus, $10,000 vehicle-loan interest).
3. If you are about to be hired, bring a U.S. passport if you have one — it is a single List A document and avoids the List B + List C combination that creates more opportunities for documentation errors. If you don't have a passport, the most common combination is a driver's license (List B) + Social Security card (List C).
4. If you are an employer, confirm your I-9 platform is using the 01/20/2025 edition (or the 08/01/2023 edition reprinted with the 05/31/2027 expiration). The 08/01/2023 printing with 07/31/2026 expiration becomes unusable on August 1, 2026.
5. Run the IRS Tax Withholding Estimator each summer. Free, 10 minutes, the single highest-leverage tax-planning tool the IRS publishes. Update your W-4 if the estimator shows you are significantly off.
6. If you are an employer and not yet enrolled in E-Verify, consider it. Even where it is not mandatory, enrollment unlocks the alternative remote inspection procedure for I-9 Section 2 — a substantial operational advantage for hiring remote employees.
7. Audit your I-9 file annually. ICE recommends self-audit as the single most effective compliance practice; the agency does not penalize errors discovered and properly remediated during a documented self-audit conducted in good faith.^[18]
8. Calendar reverification dates for List A and List C documents with expiration. Missing a reverification deadline is one of the four most common substantive violations and one of the easiest to prevent.

FAQ — the questions people actually ask