What is a 10-K/A filing?

The "/A" suffix on any SEC form means amendment. A 10-K/A is filed AFTER the original 10-K when something in that filing turns out to be wrong, incomplete, or in need of revision. The amendment carries the same filer, the same fiscal-year period, and the same EDGAR accession structure — but a new accession number and a new filing date.

Amendments are not optional once the issuer or its auditor identifies a material error. Item 4.02 of Form 8-K is the disclosure event that flags non-reliance on previously-issued financials; the 10-K/A is the follow-on filing that substantively corrects the record.

• Financial restatement. Revenue recognition error, expense misclassification, or accounting policy change requires restated historical financials in the original 10-K period.
• Part III incorporation by reference. Smaller filers commonly file Part III (executive compensation, governance, certain ownership tables) as a 10-K/A within 120 days of fiscal year-end when the proxy statement is not ready in time for the original 10-K deadline. This is a routine, non-substantive amendment.
• SEC staff comment letter. The Division of Corporation Finance reviews filings and issues comment letters. Responses that require disclosure changes get filed as a 10-K/A.
• Auditor change with prior-period restatement. A new auditor identifies issues in legacy periods; restated statements land in a 10-K/A.
• Material exhibit or signature omission. A required certification, agreement, or other exhibit was missing from the original; the 10-K/A re-files the document with the missing piece.

The two largest classes of 10-K/A are extremely different in signal value:

When researching a 10-K/A always open the cover page first. The explanatory note in Item 9B or the Explanatory Note section at the top tells you which class of amendment it is.

The 10-K/A is a complete-filing amendment — it re-files the full document with the amended sections marked. EDGAR preserves the original 10-K alongside the amendment; both are publicly accessible. The amendment's cover page explicitly identifies which items are being amended and which sections of the original 10-K remain unchanged.

Filers are required to include an explanatory note describing what is being amended and why. The CEO and CFO certifications (Sarbanes-Oxley §302 and §906) are re-executed and re-filed with the amendment. The auditor consents to the use of any restated financial statements via a new exhibit.

The base rate matters: among ~3,500 U.S. domestic SEC registrants, roughly 4-7% file at least one 10-K/A in any given year, and the great majority of those are routine Part III amendments. Restatement-class amendments are far rarer — typically 50-150 substantive restatements per year across the entire U.S. filer universe, per Audit Analytics long-run data.

A single restatement 10-K/A is not automatically a red flag — some are immaterial in dollar terms even when the non-reliance trigger fires. But repeated restatement amendments across multiple fiscal years signal recurring internal-controls weakness and almost always precede broader governance issues, auditor resignations, or restatement-driven stock-price re-pricing.

Conversely, healthy issuers with strong internal control often file Part III 10-K/A annually for years without ever filing a restatement amendment. The form is the same; the signal is the explanatory note.

• Open the cover page. Note which items are listed as amended.
• Read the Explanatory Note. This single section explains everything — class of amendment, financial impact, period affected.
• If accounting: pull the restated income statement and balance sheet. Compare to the originally-filed numbers from the superseded 10-K (still on EDGAR). The delta tells the story.
• Cross-reference the 8-K Item 4.02 filing that preceded the 10-K/A. The non-reliance disclosure often contains earlier management commentary on root cause.
• Check whether the auditor changed. A new audit firm consent exhibit on the 10-K/A signals an auditor transition during the restatement process — itself a meaningful event.

The /A suffix works the same way across all SEC forms. A 10-Q/A amends a previously-filed quarterly report — same mechanics, quarterly scope. An 8-K/A amends a previously-filed current report, most commonly used to add the audited financial statements of a recently-acquired business that were not yet available when the original 8-K was filed (Item 9.01(a)(4) has a 71-day grace period for those financials). Understanding the /A convention applies broadly across the EDGAR corpus.

SecFilingDex's 10-K/A index is at /form/10-k-a — sorted by recency. Compare against the 15 live 10-K filings at /form/10-k to see which issuers have amended recent annual reports.