Complete Guide to SEC Filing Types (All Major Forms Explained)

The SEC has over 200 form types on its books. Most investors will never encounter more than 10 of them. This guide covers every major form type that matters for investors, organized by purpose, with links to dedicated guides where applicable.

Master table: all major SEC filing types

Filing Type	Full Name	Purpose	Frequency	Who Files	Deadline
10-K	Annual Report	Comprehensive annual financial disclosure	Annually	US domestic companies	60–90 days after fiscal year end
10-K/A	Annual Report Amendment	Correction or update to a 10-K	As needed	US domestic companies	N/A
10-Q	Quarterly Report	Quarterly financial update (unaudited)	3x per year	US domestic companies	40–45 days after quarter end
10-Q/A	Quarterly Report Amendment	Correction or update to a 10-Q	As needed	US domestic companies	N/A
8-K	Current Report	Material event disclosure	As triggered	US domestic companies	4 business days after event
8-K/A	Current Report Amendment	Correction or update to an 8-K	As needed	US domestic companies	N/A
S-1	Registration Statement	IPO registration	Once (pre-IPO)	Companies going public	Before IPO
S-1/A	Registration Statement Amendment	Amendments during SEC review	Multiple	Companies going public	During IPO process
S-3	Shelf Registration	Secondary offerings by established companies	As needed	Public companies	N/A
DEF 14A	Definitive Proxy Statement	Annual meeting voting materials	Annually	US domestic companies	40+ days before annual meeting
DEFA14A	Additional Proxy Materials	Supplemental proxy solicitation materials	As needed	US domestic companies	N/A
Form 4	Statement of Changes in Beneficial Ownership	Insider stock transaction disclosure	Per transaction	Officers, directors, 10%+ holders	2 business days after transaction
Form 3	Initial Statement of Beneficial Ownership	First-time insider ownership disclosure	Once per insider	New officers/directors	10 days of becoming insider
Form 5	Annual Statement of Beneficial Ownership	Annual wrap-up of unreported transactions	Annually	Insiders with unreported transactions	45 days after fiscal year end
13-F	Quarterly Holdings Report	Institutional equity holdings disclosure	Quarterly	$100M+ investment managers	45 days after quarter end
SC 13G	Beneficial Ownership Report	Passive 5%+ ownership disclosure	As triggered / annually	Passive large shareholders	10 days of crossing 5% / Feb 15 annual update
SC 13D	Beneficial Ownership Report	Active 5%+ ownership disclosure	As triggered	Active large shareholders	10 days of crossing 5%
20-F	Annual Report (Foreign)	Annual report for foreign private issuers	Annually	Foreign private issuers	4 months after fiscal year end
20-F/A	Amendment to 20-F	Correction or update to a 20-F	As needed	Foreign private issuers	N/A
6-K	Current Report (Foreign)	Material event disclosure for foreign issuers	As triggered	Foreign private issuers	“Promptly”
40-F	Annual Report (Canadian)	Annual report for Canadian issuers (MJDS)	Annually	Eligible Canadian companies	~90 days after fiscal year end
F-1	Registration Statement (Foreign)	IPO registration for foreign companies	Once (pre-IPO)	Foreign companies going public in US	Before US IPO
NT 10-K / NT 10-Q	Notification of Late Filing	Notice that annual/quarterly report will be late	As needed	Any public company	Before original deadline

Annual and quarterly reports

10-K - Annual Report

The 10-K is the most comprehensive disclosure a US public company makes. Filed once per year, it contains audited financial statements, management’s discussion and analysis, complete risk factor disclosure, business overview, and executive compensation information. It’s the starting point for fundamental analysis of any US public company.

Filing deadline: Large accelerated filers (public float ≥$700M) have 60 days. Accelerated filers ($75M–$700M) have 75 days. Non-accelerated filers have 90 days. All deadlines measured from fiscal year end.

See our dedicated guide: What is a 10-K filing?

10-Q - Quarterly Report

The 10-Q is filed three times per year (after Q1, Q2, and Q3; the Q4 financials appear in the 10-K). It contains unaudited but independently reviewed financial statements and a shorter version of the MD&A and risk factor disclosures from the annual 10-K.

Filing deadline: Large accelerated filers have 40 days after quarter end. Accelerated filers have 40 days. Non-accelerated filers have 45 days.

20-F - Annual Report for Foreign Private Issuers

The 20-F is the annual report form for non-US companies listed on US exchanges. It covers the same ground as the 10-K but allows IFRS accounting and has a 4-month filing deadline. Major filers include Alibaba, TSMC, Shell, ASML, and Novo Nordisk.

See our dedicated guide: What is a 20-F filing?

40-F - Annual Report for Canadian Companies

Canadian companies listed on US exchanges use the 40-F, which wraps their Canadian Annual Information Form (AIF) and audited financials using the Multijurisdictional Disclosure System (MJDS). Major filers include Canadian National Railway, Barrick Gold, and Enbridge.

See our dedicated guide: What is a 40-F filing?

Current reports and event-driven filings

8-K - Current Report

When something material happens between quarterly and annual reports, US companies file an 8-K. The form has specific “Items” for different types of events (Item 2.02 for earnings releases, Item 5.02 for leadership changes, etc.). Filing deadline is 4 business days.

See our dedicated guide: What is an 8-K filing?

6-K - Current Report for Foreign Private Issuers

The 6-K is the foreign equivalent of the 8-K. Unlike the 8-K, the 6-K has no specific triggering items - it’s filed whenever the company makes material information public in its home country. Most 6-Ks are “furnished” rather than “filed,” which affects the legal liability standard.

See our dedicated guide: What is a 6-K filing?

Registration statements

S-1 - IPO Registration Statement

Before a US company can conduct an IPO, it must file an S-1. The S-1 contains the business description, audited financial statements, risk factors, use of proceeds, and management team. After SEC review and comment (often resulting in S-1/A amendments), the registration is declared effective and the IPO can proceed.

See our dedicated guide: What is an S-1 filing?

S-3 - Shelf Registration

Already-public companies that want to raise additional capital file an S-3 (a “shelf registration”). This allows them to offer securities periodically without a new S-1 review for each offering. Large established companies use shelf registrations routinely.

F-1 - Foreign Company IPO Registration

The F-1 is the S-1 equivalent for foreign companies conducting a US IPO. Major F-1 filings have included Alibaba’s 2014 IPO ($25 billion - the largest IPO in US history at the time) and many other international technology companies.

Proxy and governance filings

DEF 14A - Definitive Proxy Statement

Filed before the annual shareholder meeting, the proxy statement covers director elections, executive compensation (including the Summary Compensation Table showing CEO and named executive officer pay), the say-on-pay vote, auditor ratification, and shareholder proposals. For governance-focused investors, this is required reading.

See our dedicated guide: What is a proxy statement?

DEFA14A - Additional Proxy Materials

Supplemental proxy solicitation materials filed after the definitive proxy. Companies may file DEFA14As to respond to a proxy advisory firm’s negative recommendation, push back against activist shareholder proposals, or clarify governance matters.

Insider trading disclosures

Form 4 - Changes in Beneficial Ownership

Filed within 2 business days whenever an insider (officer, director, or 10%+ shareholder) buys, sells, or otherwise acquires or disposes of company securities. The transaction code tells you what happened: P = open market purchase (strongest signal), S = open market sale, A = equity grant, F = tax withholding.

See our dedicated guide: What is a Form 4 filing?

Form 3 - Initial Statement of Beneficial Ownership

When someone first becomes a reporting insider (newly appointed director, newly promoted executive, or shareholder crossing the 10% threshold), they file a Form 3 within 10 days establishing their initial ownership position.

Form 5 - Annual Statement of Beneficial Ownership

If an insider had any transactions during the fiscal year that weren’t previously reported, they file a Form 5 within 45 days of fiscal year end. In practice, Form 5 filings are rare because most transactions that require reporting are captured in real-time Form 4 filings.

Large shareholder disclosures

13-F - Quarterly Holdings Report

Institutional investment managers with $100 million or more in US equity assets must file a quarterly 13-F disclosing all US equity holdings. This creates the public record of hedge fund, mutual fund, and pension fund positions that investors monitor for “smart money” signals.

Key limitation: 45-day delay means the data is stale by the time it’s public.

See our dedicated guide: What is a 13-F filing?

SC 13D and SC 13G - Beneficial Ownership Reports

When any investor crosses 5% ownership of a company’s shares, they must file a beneficial ownership report. SC 13D is for “active” investors who intend to influence management (typically filed by activist hedge funds, meaning investment firms that buy large stakes and push for changes in company strategy or governance). SC 13G is for “passive” investors (index funds, long-only managers) who crossed 5% without intent to control. SC 13D requires filing within 10 days and must be amended promptly when circumstances change - this is how activist campaigns become public.

Late filing notices

NT 10-K and NT 10-Q - Notification of Late Filing

If a company won’t meet its annual or quarterly report deadline, it files an NT 10-K or NT 10-Q to notify the SEC. This grants an automatic extension - typically 15 additional days for 10-Ks (5 days for 10-Qs). A late filing notice can itself be a red flag, particularly if filed shortly before results are due and accompanied by vague language about the reasons for the delay.

Which filings matter most for investors?

The right forms to follow depend on your investment approach:

Long-term fundamental investors should focus on the 10-K (annually) and 10-Q (quarterly). These are the core financial disclosure documents. For companies you own, plan to read at least the MD&A and risk factors each year.

Event-driven investors will rely heavily on the 8-K, which captures material events as they happen. Earnings, leadership changes, acquisitions - they all flow through 8-Ks. Real-time 8-K alerts are essential for this style.

Governance-focused investors should read the DEF 14A (proxy statement) annually. This is where executive compensation, board quality, and shareholder proposal outcomes are disclosed.

Smart money trackers will want the 13-F (quarterly) for institutional positions and Form 4 (ongoing) for insider transactions. Remember the 45-day delay on 13-Fs.

IPO investors should read the S-1 and S-1/A before the IPO. Reading the S-1 is the best due diligence you can do on a newly public company.

International stock investors need the 20-F (annually) and 6-K (ongoing) for foreign private issuers. Canadian companies use 40-F instead of 20-F.

How to set up alerts for SEC filings

For the filings that matter to you, see our guide to SEC filing alerts - which covers free methods including AssetRoom (with AI summaries) and EDGAR RSS feeds.