Complete guide to SEC filing types. Learn what each form contains, when it's filed, and why it matters for your investment research.
The SEC requires public companies to file dozens of different forms. This guide covers the ones that matter most for investment research—what they contain, when they're filed, and why you should read them.
Quick Reference: Most Important SEC Filings
| Form | Name | Frequency | Priority |
|---|---|---|---|
| 10-K | Annual Report | Yearly | ⭐⭐⭐⭐⭐ |
| 10-Q | Quarterly Report | 3x/year | ⭐⭐⭐⭐ |
| 8-K | Current Report | As needed | ⭐⭐⭐⭐⭐ |
| DEF 14A | Proxy Statement | Yearly | ⭐⭐⭐ |
| S-1 | IPO Registration | Once | ⭐⭐⭐⭐⭐ |
| Form 4 | Insider Transactions | As needed | ⭐⭐⭐ |
| 13F | Institutional Holdings | Quarterly | ⭐⭐⭐ |
Periodic Reports (Regular Schedule)
Form 10-K: Annual Report
What it is: The most comprehensive annual disclosure of a company's business and finances.
Filing deadline:
- Large accelerated filers (>$700M float): 60 days after fiscal year end
- Accelerated filers ($75M-$700M): 75 days
- Non-accelerated filers (<$75M): 90 days
Key contents:
- Part I: Business description, risk factors, properties
- Part II: MD&A, audited financial statements, selected financial data
- Part III: Directors, executive compensation, governance
- Part IV: Exhibits and signatures
Why it matters: The 10-K is your primary source for understanding any company. Read it before making any significant investment.
**Deep dive: How to Read a 10-K in 15 Minutes →**
Form 10-Q: Quarterly Report
What it is: Quarterly financial update filed for Q1, Q2, and Q3 (Q4 is covered by the 10-K).
Filing deadline:
- Large accelerated filers: 40 days after quarter end
- Accelerated filers: 40 days
- Non-accelerated filers: 45 days
Key contents:
- Condensed (unaudited) financial statements
- MD&A for the quarter
- Updated risk factors (material changes only)
- Controls and procedures update
Why it matters: 10-Qs let you track performance between annual reports. Spot trends before they crystallize.
**Deep dive: Form 10-Q Explained →**
Current Reports (Event-Triggered)
Form 8-K: Current Report
What it is: Real-time disclosure of material events that shareholders need to know immediately.
Filing deadline: Within 4 business days of the triggering event.
Common triggers:
- Leadership changes (CEO, CFO departures)
- Mergers and acquisitions
- Bankruptcy or receivership
- Earnings announcements
- Material contracts
- Cybersecurity incidents
Why it matters: 8-Ks contain breaking news that can move stock prices overnight. Set up alerts for companies you own.
**Deep dive: 8-K Filings Decoded →**
Governance and Compensation
DEF 14A: Proxy Statement
What it is: Information provided to shareholders before annual meetings, including items for voting.
Filing timing: Before annual shareholder meeting (typically in spring).
Key contents:
- Board member bios and qualifications
- Executive compensation details
- Audit committee report
- Proposals for shareholder vote
- Related party transactions
Why it matters: Proxy statements reveal how much management is paid, potential conflicts of interest, and governance quality.
Form 4: Insider Transactions
What it is: Report of transactions by company insiders (executives, directors, 10%+ shareholders).
Filing deadline: Within 2 business days of the transaction.
What it shows:
- Shares bought or sold
- Option exercises
- Gifts of stock
- Automatic (10b5-1) plan transactions
Why it matters: Insider buying is often bullish. Heavy insider selling can be concerning (though has many innocent explanations).
Registration Statements
Form S-1: IPO Registration
What it is: Registration statement filed before a company goes public through an IPO.
Key contents:
- Business description
- Historical financials
- Risk factors
- Use of proceeds
- Management bios
- Principal shareholders
Why it matters: The S-1 is your only source of deep research before a company starts trading. Contains more detail about private-stage metrics.
Form S-3: Shelf Registration
What it is: Allows established companies to sell securities "off the shelf" quickly without full registration.
Why it matters: An S-3 filing often precedes a stock offering, which can dilute existing shareholders.
Form S-4: Business Combination
What it is: Registration for securities issued in mergers, acquisitions, or business combinations.
Why it matters: Contains details of deal terms, pro forma financials, and reasons for the transaction.
Institutional Filings
Form 13F: Quarterly Holdings
What it is: Quarterly report of equity holdings by institutional investment managers with $100M+ in assets.
Filing deadline: 45 days after quarter end.
What it shows:
- All equity positions over $100M
- Shares held at quarter end
- Market value of positions
Why it matters: Track what major investors (hedge funds, mutual funds) are buying and selling.
Schedule 13D: Beneficial Ownership (Activist)
What it is: Filed when an investor acquires 5%+ of a company's shares with activist intent.
Filing deadline: Within 10 days of crossing 5%.
Why it matters: 13D filings often precede activist campaigns, takeover attempts, or strategic changes. Potentially stock-moving.
Schedule 13G: Beneficial Ownership (Passive)
What it is: Like 13D, but for passive investors who don't intend to influence company management.
Why it matters: Shows major institutional accumulation without activist intent.
Other Important Filings
Form 144: Intent to Sell Restricted Stock
What it is: Notice of intent to sell restricted or control securities.
Why it matters: Large Form 144 filings can indicate significant insider selling ahead.
NT 10-K / NT 10-Q: Notification of Late Filing
What it is: Filed when a company can't meet its 10-K or 10-Q deadline.
Why it matters: Late filings are a red flag. The notification must explain why—often revealing internal problems.
10-K/A, 10-Q/A: Amended Filings
What it is: Corrections or amendments to previously filed reports.
Why it matters: Amended filings can signal errors, restatements, or SEC-required changes. Always read the "Explanatory Note."
Filing Lookup Cheat Sheet
| When you want to know... | Read this form... |
|---|---|
| Everything about a company | 10-K |
| Recent quarterly performance | 10-Q |
| Breaking news or events | 8-K |
| Executive compensation | DEF 14A |
| Pre-IPO company details | S-1 |
| What insiders are buying/selling | Form 4 |
| Hedge fund holdings | 13F |
| Activist investor activity | 13D |
| Stock offering coming | S-3 |
| M&A transaction details | S-4 |
Where to Find All These Filings
All SEC filings are free on EDGAR:
- Search by company name or ticker
- Filter by form type
- Download in HTML, TXT, or XBRL format
**Learn more: How to Use EDGAR →**
Using AI to Analyze SEC Filings
With so many filing types, research can feel overwhelming. MoneySense AI helps by:
- Summarizing key sections in seconds
- Identifying bullish and bearish signals
- Tracking changes between filings
- Highlighting what matters most
Related Articles
- **How to Read a 10-K in 15 Minutes** — Efficient annual report analysis
- **Form 10-Q Explained** — Quarterly report deep dive
- **8-K Filings Decoded** — Understanding current reports
- **5 Red Flags in SEC Filings** — Warning signs to watch
Navigate SEC filings like a pro. Try MoneySense AI for instant analysis of any filing—10-K, 10-Q, 8-K, or beyond.