Form 4 Amendment (Form 4/A): A Compliance Officer's Filing Guide

A Form 4 amendment, filed on EDGAR as "Form 4/A," is how corporate insiders correct errors or omissions in a previously filed Form 4. The mechanics look simple. The consequences of getting them wrong are not: late amendments can trigger proxy disclosure obligations, and intentional misstatements carry criminal liability under 18 U.S.C. § 1001 and 15 U.S.C. § 78ff(a).

This guide is written for compliance officers, general counsel, and equity plan administrators who need to move from error discovery to a clean EDGAR filing, without creating new problems in the process.

Key takeaway: The amendment decision is not just a technical filing question. It is a materiality judgment, a proxy disclosure assessment, and a legal responsibility question, all at once. Work through each in sequence before touching EDGAR.

What Is a Form 4 Amendment and When Is It Required?

A Form 4/A is a corrective filing that replaces specific line items in a previously filed Form 4. It is not a full re-filing of the original. The SEC's Form 4 instructions confirm that the form and any amendment is deemed filed on the date it is received by the Commission.

An amendment is required when the original Form 4 contains an error or omission material enough to mislead investors about the insider's transactions, beneficial ownership totals, or reporting status. Not every mistake clears that bar. The threshold question is materiality, and it governs everything that follows.

For context on what triggers the original Form 4 obligation, see What Transactions Trigger a Form 4 Filing Under Section 16?

Step 1: Apply the Materiality Test Before Filing Anything

Before preparing a Form 4/A, assess whether the error is material enough to require one. Filing an unnecessary amendment wastes resources and can draw attention to minor discrepancies that would otherwise pass unnoticed. Failing to file a necessary one is worse.

Alan Dye, partner at Hogan Lovells and editor of Section16.net, a leading Section 16 authority, frames the materiality test around three questions, as cited in NASPP's guidance on correcting Form 4 mistakes:

1. Does the error have any potential to mislead investors about something important to the purposes of Section 16(a)?
2. Was transactional information reported correctly?
3. Did the filing accurately report the insider's status as an officer or director?

If transactional data and beneficial ownership totals are correct, and the insider's officer or director status is accurately reflected, an amendment is likely not required. Examples of errors that typically do not require amendment include minor formatting issues, inconsequential footnote wording, or clerical details that do not affect the substance of what was reported.

Examples of errors that almost always require amendment:

• Wrong number of shares in a transaction (Column 4 of Table I)
• Incorrect beneficial ownership total (Column 5 of Table I or Column 9 of Table II)
• A transaction coded as a disposition when it was an acquisition (or vice versa)
• Incorrect check or omission of the Rule 10b5-1(c) plan checkbox (see Step 5 below)
• A duplicate grant reported twice
• Wrong grant type in Column 1 of Table II

When in doubt, involve outside Section 16 counsel. The materiality call is a legal judgment, not an administrative one.

Step 2: Identify the Scope of the Amendment

The amendment should include only the line items being corrected, not a full re-filing of all original data. This is both the SEC's instruction and the practical standard confirmed by NASPP's practitioner guidance.

A real-world example illustrates the scope principle well. When Matador Resources EVP Van H. Singleton II filed a Form 4/A on May 4, 2015, amending an original filed April 27, 2015, the amendment restated only the single Table I line affected: the number of shares withheld for taxes upon restricted stock vesting. The corrected figure was 1,981 shares withheld (down from the original estimate), increasing beneficial ownership reported to 30,411 shares. Nothing else in the original filing was restated.

This is the most common Form 4/A scenario in practice: a tax withholding estimate on restricted stock vesting that is later corrected once the final tax liability is calculated. The initial filing uses an estimated withholding number; the final calculation produces a different share count; the amendment corrects the record.

Do you need to amend every subsequent Form 4 that carried the error forward? In most cases, no. Updating the next Form 4 with correct information is generally acceptable, per NASPP guidance. The amendment corrects the record at the point of error; subsequent filings that reflected the erroneous figure do not each require their own 4/A, provided the next filing restores accurate totals.

One important exception: if the error involves an omitted transaction rather than a misreported one, a Form 4/A alone may not be sufficient. An omitted transaction that should have been reported on Form 4 may require a new Form 4 (or, in limited circumstances, a Form 5). That is a different legal situation with different consequences. See Form 5 Filing Requirements for when the annual Form 5 can absorb a late-reported transaction.

Step 3: File the Form 4/A on EDGAR

On EDGAR, the amendment is filed using document type "4/A." This is the technical signal to the system, and to investors, that the filing is corrective. EDGAR links the 4/A to the original filing in the issuer's filing history, so the amendment is immediately visible alongside the original.

Here is the field-by-field checklist for a Form 4/A:

Most companies file through a third-party filing agent (Workiva, Donnelley Financial Solutions, or a dedicated Section 16 filing platform) rather than directly through EDGAR's online system. If your company uses a filing agent, confirm that the agent is submitting under document type 4/A and that Field 4 is populated with the correct original filing date. A 4/A submitted without Field 4 completed will not properly link to the original on EDGAR.

The SEC's EDGAR system maintains a searchable index of all Form 4/A filings, which is publicly accessible in real time.

Step 4: Draft the Amendment Footnote

Every Form 4/A requires a footnote in the Explanation of Responses section explaining what was wrong and what was corrected. The footnote does not need to be lengthy, but it must be specific enough that an investor reading the amendment understands what changed and why.

The Matador Resources footnote is a useful model:

"The original Form 4 is being amended by this Form 4/A to reduce the number of shares actually withheld by the Issuer and increase the amount of securities beneficially owned following the transaction after final calculation of the resulting tax liability."

That is 43 words. It identifies the direction of the correction (reduce shares withheld, increase beneficial ownership), the reason (final tax calculation), and the mechanism (net share settlement). Nothing more is needed.

For other error types, apply the same structure: state what was wrong, state what is correct, and state why the discrepancy occurred. Avoid over-explaining. A footnote that speculates about causes or includes unnecessary legal hedging can create more questions than it answers.

Common footnote patterns by error type:

• Duplicate grant: "This Form 4/A is filed to correct the original Form 4, which inadvertently reported [grant description] twice. The duplicate entry has been removed. No disposition of securities occurred."
• Wrong transaction code (A vs. D): "This Form 4/A corrects an error in Column 5 of Table II of the original Form 4, in which [number] Share Units were shown as a disposition rather than an acquisition. The correct entry reflects an acquisition."
• Incorrect beneficial ownership total: "This Form 4/A corrects the amount of securities beneficially owned reported in Column 5 of Table I of the original Form 4. The correct amount is [X] shares."

The MGIC Investment Corp Form 4/A for director Curt S. Culver follows exactly this pattern: the amendment footnote identifies the specific column and table that was wrong, describes the error (shares shown as a disposition instead of an acquisition), and states that only the affected lines are being restated, per Instruction 9(b) to Form 4.

Step 5: Handle the Rule 10b5-1 Plan Checkbox

The Form 4 includes a checkbox to indicate that a transaction was made pursuant to a Rule 10b5-1(c) plan. This checkbox was added following the SEC's December 2022 amendments to Rule 10b5-1, and it appears on the current form (revised March 2026, OMB approval expires August 31, 2029).

An error in this checkbox, whether incorrectly checked or omitted when it should have been checked, is a material error that requires a Form 4/A. The reason: the 10b5-1 checkbox is directly tied to the affirmative defense analysis under Rule 10b5-1(c). Investors, proxy advisory firms, and the SEC use this checkbox to assess whether insider trades were pre-planned. A wrong entry misrepresents the nature of the transaction.

If the original Form 4 omitted the checkbox for a transaction that was in fact made under a qualifying 10b5-1 plan, file a Form 4/A with the checkbox correctly marked and a footnote identifying the correction. The reverse applies if the box was checked in error.

For a full treatment of 10b5-1 plan requirements, see the Rule 10b5-1 Trading Plan Requirements 2026 Compliance Guide.

Step 6: Assess the Item 405 Proxy Disclosure Consequence

If the Form 4/A is filed after the two-business-day deadline that applied to the original filing, the company must assess whether the late filing requires disclosure in the annual proxy statement.

Item 405 of Regulation S-K (17 CFR § 229.405) requires companies to disclose in their proxy statement whether any director or officer failed to file required Section 16 reports on a timely basis during the prior fiscal year. A Form 4/A filed after the original deadline is, by definition, a late filing, and Item 405 disclosure may be required.

The practical test:

• Was the original Form 4 filed on time (within two business days of the transaction)?
• If yes, and the amendment is filed promptly after error discovery, the original filing was timely even if the amendment is not. The Item 405 analysis turns on whether the original filing was late, not whether the amendment is.
• If the original Form 4 itself was late, or if the amendment corrects an omitted transaction that was never reported at all, Item 405 disclosure is almost certainly required.

Companies typically handle Item 405 disclosure in the proxy under a heading such as "Section 16(a) Beneficial Ownership Reporting Compliance," naming the reporting person, the number of late reports, and the number of transactions not timely reported. The disclosure is factual and brief, but it is public and visible to institutional investors and proxy advisory firms.

Step 7: Understand Who Bears Legal Responsibility

The reporting person, not the company, is legally responsible for the accuracy and timeliness of the Form 4. The SEC Form 4 signature page carries this warning on its face: "Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a)."

In practice, companies almost always handle the administrative process of filing on behalf of the insider, often through an attorney-in-fact arrangement. The Matador Resources Form 4/A, for example, was signed "/s/ Van H. Singleton, II, by Kyle A. Ellis as attorney-in-fact." The MGIC Investment Corp Form 4/A was signed by "Dan D., Attorney-in-Fact" under a previously filed power of attorney.

The attorney-in-fact arrangement is operationally efficient, but it does not transfer legal liability. The insider remains responsible. This means compliance teams should document the error discovery, the materiality assessment, the amendment decision, and the filing date, and retain that documentation. If the SEC ever asks, the paper trail demonstrates a functioning control environment rather than a systemic failure.

Enforcement Risk: When Does the SEC Actually Act?

A single late Form 4/A rarely draws SEC enforcement action. The SEC's enforcement posture on Section 16(a) focuses on patterns: systematic failures to file, repeated late filings across multiple insiders, or material misstatements that appear to conceal transactions. The SEC's litigation releases reflect cease-and-desist orders, civil monetary penalties, and disgorgement actions against companies and insiders with chronic Section 16 compliance failures, not isolated amendments.

That said, the risk calculus changes in two situations:

• The error involves a transaction that could trigger short-swing profit disgorgement under Section 16(b). An amendment that reveals a previously unreported purchase, combined with a sale within six months, can expose the insider to disgorgement liability regardless of intent. See the Short-Swing Profit Rule: Definition, How It Works, and 2026 Updates for the mechanics.
• The error is discovered long after the original filing, in a context where the SEC might view the delay in correction as deliberate concealment rather than administrative oversight.

Proxy advisory firms (ISS and Glass Lewis) and activist shareholders also monitor Form 4/A filings as governance signals. A pattern of amendments, particularly for the same insider or the same type of error, can appear in proxy analyses as evidence of weak internal controls over insider reporting.

Common Error Scenarios and Recommended Treatment

Form 4 Amendment Compliance Checklist

Use this sequence from error discovery to filed amendment:

1. Identify the error. Document exactly what is wrong, which field, which table, which line.
2. Apply the materiality test. Run through the Dye framework: transactional data correct? Beneficial ownership correct? Insider status correct? Involve counsel if the answer to any is no.
3. Determine the correct form. If the error is a misreported transaction, file a Form 4/A. If the error is an omitted transaction, assess whether a new Form 4 or Form 5 is required.
4. Scope the amendment. Identify only the line items to be corrected. Do not restate the entire original filing.
5. Draft the footnote. State what was wrong, what is correct, and why. Keep it specific and brief.
6. Check the 10b5-1 checkbox. Confirm whether the affected transaction was made under a qualifying plan and whether the checkbox status needs correction.
7. File on EDGAR as document type 4/A. Populate Field 4 with the original filing date. Confirm the filing agent has done the same if using a third party.
8. Assess Item 405. Determine whether the original filing was timely. If the amendment is filed after the original deadline, evaluate proxy disclosure obligations with counsel.
9. Document everything. Retain records of the error discovery, materiality analysis, amendment decision, and filing confirmation.
10. Update the next Form 4. Confirm that the next filing reflects correct beneficial ownership totals going forward.

FAQ

Is there a deadline for filing a Form 4 amendment? No separate deadline applies to Form 4/A filings. The SEC's position is that amendments should be filed promptly upon discovery of an error. However, if the amendment is filed after the two-business-day deadline that applied to the original transaction, the late filing may trigger Item 405 proxy disclosure.

Can one Form 4/A fix multiple errors from the same original filing? Yes. A single Form 4/A can correct multiple errors in the same original Form 4. Include all affected line items and a footnote that addresses each correction. There is no requirement to file separate amendments for each error.

What is the difference between Form 3 and Form 4 for Section 16 purposes? Form 3 is the initial statement of beneficial ownership filed when a person first becomes a Section 16 reporting person (within 10 calendar days). Form 4 reports changes in beneficial ownership and must be filed within two business days of each transaction. Form 3 establishes the baseline; Form 4 updates it. See the Form 3 vs. Form 4 vs. Form 5 comparison for a full side-by-side.

Do I need to amend every subsequent Form 4 that carried the error forward? Generally no. Correcting the original filing and updating the next Form 4 with accurate totals is the accepted practice. Amending every intermediate filing is not required unless those filings themselves contain independently material errors.

What if the error involves a transaction that was never reported at all? An omitted transaction is not corrected by a Form 4/A alone. A new Form 4 is required to report the transaction, or in limited circumstances the transaction can be reported on the annual Form 5. The legal consequences differ from a simple amendment because the original reporting obligation was never met. See Form 5 Filing Requirements for when Form 5 can absorb late-reported transactions.

Who signs the Form 4/A? The reporting person signs, or an attorney-in-fact signs on their behalf under a valid power of attorney. The criminal liability warning on the signature page applies regardless of who signs. The insider remains legally responsible for the accuracy of the filing.