How to read SEC filings

Almost everything a public company does leaves a paper trail at the SEC. These explain what each filing is, what triggers it, and which ones are worth your attention.

• Financial terms explained

  Market cap, P/E, free cash flow, shareholder equity — what the numbers on a company page mean, and what they do not.

  21 terms
• Form 10-K: The Annual Report the SEC Requires

  The 10-K is the comprehensive annual filing that public companies submit to the SEC, containing audited financials, a description of the business, risk factors, and management's discussion — far more complete than the glossy shareholder letter.

  10-K 10-K/A 10-KSB
• Form 10-Q: The Quarterly Report (and Why Q4 Is Missing)

  Form 10-Q is the quarterly financial report publicly traded companies file with the SEC — but only three are filed each year because the fourth quarter is covered by the annual 10-K. This explainer covers the filing schedule, the lighter review standard versus an audit, the shorter deadline, and how to extract Q4 numbers by subtraction.

  10-Q 10-Q/A
• Form 8-K: The Current Report for Material Events

  Form 8-K is the SEC filing companies use to disclose major events that shareholders need to know about immediately, with a four-business-day deadline and specific item numbers that instantly tell experienced readers what happened.

  8-K 8-K/A
• Form 4: Insider Transactions – How to Read Them Without Being Misled

  Form 4 is the SEC filing that corporate insiders must submit within two business days of buying or selling their own company's stock; knowing how to decode its transaction codes can help you distinguish meaningful signals from routine noise.

  4 4/A
• Forms 3 and 5: The Bookends of Insider Reporting

  Form 3 is the initial statement filed when someone becomes an insider; Form 5 is the annual catch-up for transactions exempt from immediate reporting. Together they bookend an insider's disclosure obligations.

  3 5 3/A 5/A
• Schedule 13D

  Schedule 13D is the SEC filing required when an investor acquires more than 5% of a public company's stock with the intent to influence or change control—it tells you who is building a stake and what they plan to do.

  SC 13D SC 13D/A
• Schedule 13G: The Passive Beneficial Ownership Filing

  Schedule 13G is a streamlined SEC filing for investors who cross 5% ownership of a company's stock but have no intention of influencing control or management — used by index funds, pension funds, and other passive institutions.

  SC 13G SC 13G/A
• Form 13F: What Big Funds Held, 45 Days Ago

  Form 13F is a quarterly SEC filing that reveals the long equity holdings of investment managers with at least $100 million in US stocks, subject to a 45-day delay that makes it a historical snapshot rather than a current signal.

  13F-HR 13F-HR/A
• Form 25: The SEC's Delisting and Bond Maturity Notice

  Form 25 notifies the SEC that a security has been removed from a national exchange. It covers both dramatic delistings (company kicked out or voluntarily leaving) and routine events like a bond being repaid at maturity. Most Form 25 filings are the boring kind.

  25 25-NSE
• Form 15: Going Dark — When a Public Company Stops Reporting to the SEC

  Form 15 notifies the SEC that a company is terminating its registration and will no longer file quarterly, annual, or other reports. It allows a company to 'go dark' but does not remove the stock from trading.

  15-12B 15-12G 15F-12B
• Form S-1: The Registration Statement Behind an IPO

  Form S-1 is the document a company files with the SEC to register new securities for sale to the public, most famously used for initial public offerings (IPOs).

  S-1 S-1/A
• Shelf Registrations and Takedowns: S-3 and 424B5

  An S-3 shelf registration is permission to sell securities later; a 424B5 takedown is the actual sale. The shelf itself is routine, but a takedown often signals dilution or capital needs.

  S-3 424B5
• Proxy Statement (DEF 14A)

  The proxy statement is the document companies send shareholders before the annual meeting, containing executive pay details, board elections, and all items up for a shareholder vote — and it's written in plain English, making it the most readable SEC filing most investors ignore.

  DEF 14A PRE 14A
• Merger Filings: The Paperwork of Being Acquired (DEFM14A, S-4, 425)

  When one company buys another, it files a stack of SEC forms—DEFM14A, S-4, and 425—that reveal the deal price, the deal's history, and the board's fairness opinion.

  DEFM14A PREM14A S-4 425
• Tender Offers (SC TO-T, SC TO-I, SC 14D9): How Public Companies Buy Shares — or Are Bought

  When someone offers to buy a significant number of shares directly from stockholders, they file a tender offer statement with the SEC. These filings (SC TO-T for third-party bids, SC TO-I for the company itself, SC 14D9 for the board's response) reveal the offer price, conditions, and whether the board thinks you should accept.

  SC TO-T SC TO-I SC 14D9
• Form NT: When a Company Can’t File Its Annual or Quarterly Report on Time

  Form NT (Notification of Late Filing) is a placeholder document that companies file with the SEC to acknowledge they will miss the deadline for their 10-K, 10-Q, or 20-F report, granting them a short grace period and requiring them to explain the delay.

  NT 10-K NT 10-Q NT 20-F
• SEC Comment Letters (UPLOAD & CORRESP): The Regulator's Questions in Public

  UPLOAD and CORRESP filings reveal the private back-and-forth between SEC staff and public companies about accounting treatments, disclosure adequacy, and other reporting issues — and they become public once the review is finished.

  UPLOAD CORRESP
• Forms 20-F, 40-F and 6-K: How Foreign Companies Report to the SEC

  Foreign companies listed on U.S. exchanges file annual reports on Form 20-F (or 40-F for Canadian issuers under the Multijurisdictional Disclosure System) and update the market with material news on Form 6-K, often with less frequent and less detailed interim reporting than domestic filers.

  20-F 40-F 6-K