All SEC filing types, explained

Q: What does the "/A" suffix mean?

Amendment. Any form name ending in /A (10-K/A, 10-Q/A, 8-K/A, 4/A, etc.) is an amended version of a previously filed document. Amendments are common and not in themselves negative signals.

The SEC's EDGAR system accepts hundreds of distinct form types. This is a working reference to the ones you actually encounter in practice — what each form is, who files it, and when.

Periodic financial reports

These are the scheduled, recurring disclosures every U.S. public company has to file.

10-K — annual report with audited financials, risk factors, business description, MD&A. Filed 60–90 days after fiscal year-end depending on company size.
10-Q — quarterly report with unaudited financials. Filed 40–45 days after quarter-end. No 10-Q is filed for the fourth quarter — the 10-K covers it.
8-K — current report for material events that happen between scheduled filings. Filed within 4 business days of the event.
20-F — annual report for foreign private issuers. Roughly equivalent to a 10-K but with disclosures tailored to non-U.S. companies.
6-K — current report for foreign private issuers. Roughly equivalent to an 8-K.
40-F — annual report for certain Canadian filers under the multijurisdictional disclosure system.
10-K/A, 10-Q/A, 8-K/A — amendments to previously filed reports. The /A suffix always indicates an amendment.

Insider transactions (Section 16)

These are filed by officers, directors, and 10%+ owners reporting their personal transactions in company stock.

Form 3 — initial statement of beneficial ownership. Filed when someone first becomes an insider.
Form 4 — statement of changes in beneficial ownership. Filed within 2 business days of each transaction. The form quants and traders watch most closely. See Form 4 transaction codes.
Form 5 — annual statement of changes. Captures transactions that were exempt from Form 4 reporting.
Form 144 — notice of proposed sale of restricted securities. Filed *before* the sale. See Form 4 vs Form 144.

Large position holders

Disclosures triggered when an investor crosses a beneficial ownership threshold.

Schedule 13D — filed by anyone who acquires more than 5% of a company's voting stock with intent to influence control. Filed within 10 days. Activist filings live here.
Schedule 13G — short-form alternative to 13D for passive investors who pass 5% but don't intend to influence control. Filed annually rather than within 10 days.
Schedule 13D/A, 13G/A — amendments triggered by material changes in position or intent.
Form 13F-HR — quarterly holdings report for institutional investment managers with $100M+ in qualifying assets. Filed within 45 days of quarter-end.
Form 13F-NT — notice filing used when a manager's holdings are already reported by another.
Form 13F-CTR — confidential treatment request for delayed disclosure of certain positions.

Securities offerings and registrations

S-1 — initial registration statement for new public offerings. The form behind every IPO.
S-3 — short-form registration for follow-on offerings by existing public companies.
S-4 — registration statement for securities issued in business combinations (M&A consideration).
S-8 — registration for employee benefit plan offerings (stock-based compensation).
F-1, F-3, F-4 — equivalent forms for foreign private issuers.
424B — prospectus filings (the "B" suffix indicates which subsection of Rule 424 the filing falls under).
POS AM — post-effective amendment to a registration statement.

Proxy materials

Filed in connection with shareholder votes (annual meetings, mergers, governance changes).

DEF 14A — definitive proxy statement. The main proxy document sent to shareholders. Contains executive compensation, board nominees, shareholder proposals, and voting matters.
PRE 14A — preliminary proxy statement, filed before the definitive version.
DEF 14C / PRE 14C — information statements (used when no vote is being solicited).
DEFA14A — additional proxy soliciting materials (often related to contested votes).

Tender offers, mergers, and going private

SC TO-T, SC TO-I — tender offer statements. TO-T is by a third party, TO-I is by the company itself (issuer self-tender).
SC 14D9 — issuer's recommendation regarding a tender offer.
SC 13E3 — going-private transaction statement.
DEFM14A — definitive merger proxy.

Investment companies (mutual funds, ETFs, closed-end funds)

N-1A — registration of open-end management investment companies (most mutual funds and ETFs).
N-CSR, N-CSRS — certified annual and semi-annual shareholder reports for registered management investment companies.
N-PORT — monthly portfolio holdings for funds; the first three months of each quarter are filed confidentially, with the third month becoming public.
N-PX — proxy voting record disclosure.

Specialized forms

NT 10-K, NT 10-Q — notification of inability to timely file. The infamous "NT" filings. Repeated NT 10-Ks are a credit-watch signal.
15-12B, 15-12G, 15-15D — termination of registration filings (the company is going dark).
TA-1, TA-2 — transfer agent forms.
ABS-EE, ABS-15G — asset-backed securities disclosures.

How EdgarKit handles all of these

Every form type listed above is ingested in real time by EdgarKit. You can filter the API by form_type to get just what you need:

# All 10-Ks filed in the last 7 days
curl "https://api.edgarkit.com/v1/filings?form_type=10-K&since=2026-06-11&limit=50" \
  -H "Authorization: Bearer YOUR_API_KEY"

# All Form 4 open-market purchases above $250k
curl "https://api.edgarkit.com/v1/filings?form_type=4&transaction_code=P&min_value=250000" \
  -H "Authorization: Bearer YOUR_API_KEY"

# All 8-Ks for a specific ticker
curl "https://api.edgarkit.com/v1/filings?form_type=8-K&ticker=NVDA" \
  -H "Authorization: Bearer YOUR_API_KEY"

You can also subscribe to webhooks scoped to specific form types, tickers, or other filters.

FAQ

How many distinct form types does EDGAR accept?

Hundreds, when you count every amendment variation and specialized form. In practice, fewer than 30 form types make up the vast majority of filings that matter for trading, research, or compliance.

What's the most common form type?

Form 4. There are typically thousands of Form 4 filings per week across all U.S. public companies.

Where can I see the SEC's official list?

The SEC publishes a complete EDGAR Form Type List. It's the source of truth but is organized by regulatory section rather than by practical use.

What does the "/A" suffix mean?

Amendment. Any form name ending in /A (10-K/A, 10-Q/A, 8-K/A, 4/A, etc.) is an amended version of a previously filed document. Amendments are common and not in themselves negative signals.