SEC Filing Analysis: Beyond Form 4
Whenever public companies or their insiders make trades, the SEC demands disclosure through official filings. These SEC filings – from Form 3 through Form 5, plus Schedule 13D/13G and others – provide a wealth of information for investors¹.
Public companies, officers, directors or anyone owning >10% of a stock must file these documents², which investors use to gauge confidence or concern. The most famous of these is Form 4 (insider trades), but it's only one piece of the puzzle.
In this guide we'll survey all the key insider-related filings, with real examples, to help you "read between the lines." We'll keep it candid and approachable – think of it as a conversation about smart ways to scan these filings and spot trading signals³.
The Complete SEC Filing Ecosystem
Form 3 – an insider's initial ownership report (due within 10 days of becoming a director/officer or >10% owner)⁴.
Form 4 – reports each change in insider holdings (purchases or sales) within 2 business days of the transaction⁵.
Form 5 – an annual summary (due 45 days after fiscal year-end) reporting any transactions that were exempt or missed on Form 4⁶.
Schedule 13D/13G – filings by any person or group buying more than 5% of a stock. Schedule 13D is used by active/activist buyers (with full details, due in days), while 13G is a simpler report for passive investors⁷.
Form 144 – a notice of intent by an insider or affiliate to sell restricted stock (often after an IPO lock-up), required when planned sales exceed 5,000 shares or $50,000 in a quarter⁸.
Form 13F – a quarterly report by institutional money managers (>$100 M AUM) listing their holdings, which can show what "smart money" is doing⁹.
Each form has its own purpose. Understanding them all gives a richer picture than Form 4 alone. For example, legendary investor Peter Lynch quipped, "There are many reasons officers might sell… But there's only one reason that insiders buy: They think the stock is undervalued."¹⁰
In practice, insider buys often signal confidence, whereas sells may have many explanations – liquidity needs, diversification, or automated plans – so context is key.
Section 16 Filings (Forms 3, 4, 5, 144)
Section 16 of the Exchange Act requires insiders – defined as officers, directors or >10% owners¹¹ – to disclose their holdings and trades. The primary forms are 3, 4, and 5:
Form 3 (Initial Statement)
When someone becomes an insider (e.g. a new CEO or director), they file Form 3 within 10 days to report existing ownership¹². This is basically a starting balance of shares/options.
Form 4 (Current Report of Changes)
After that, any time the insider buys or sells shares (or options) of the company, a Form 4 must be filed within two business days of the transaction¹³.
The Form 4 lists each transaction date, type (buy or sell), amount, price, and resulting holdings. Each transaction uses a code to describe its nature: for example, "P" for purchase and "S" for sale¹⁴. Insiders even use code "D" if they transfer stock back to the company, or "A" for a grant/award (like option exercise)¹⁵.
Form 5 (Annual Summary)
Some small transactions are exempt from immediate reporting (e.g. insider purchases under $10K in a 6-month window). In such cases or for any missed entries, a Form 5 is filed 45 days after fiscal-year end to catch up¹⁶.
You rarely see Form 5s unless there were unusual circumstances; most trades should already appear on Form 4.
Form 144 (Notice of Sale)
This is a special disclosure for insiders planning to sell restricted stock (often from lock-up agreements after IPOs). If an insider intends to sell more than 5,000 shares or $50,000 worth within a 3-month span, they must file Form 144 as notice of intent¹⁷.
It doesn't detail the actual sale price, but it tells you roughly how many shares could flood the market soon. For example, after an IPO, insiders are typically blocked from selling for 120–180 days, so a Form 144 could signal a big planned selloff at lock-up expiry¹⁸.
Real-World Form 4 Example
For investors, these filings are public: you can pull them from the SEC's EDGAR database¹⁹ or many aggregator sites. A quick look at a Form 4 might show something like this snippet (from a real filing on Cibus Inc., ticker CBUS). Here Director Gerhard Prante reported two sales of 1,150 shares each (transaction code "S") on Jan 3 and Jan 6, 2025, at prices of ~$2.89 and $3.14²⁰:
| Date | Txn | Shares | Price | Shares Held After | |------|-----|--------|-------|-------------------| | 01/03/2025 | S | 1,150 | $2.89 | 50,257 | | 01/06/2025 | S | 1,150 | $3.14 | 49,107 |
Such a Form 4 is coded "S" (sale) because Prante is disposing of shares²¹. The footnote indicates these sales were "automatically pursuant to a Rule 10b5-1 plan"²² – meaning they were pre-scheduled, which often reduces their informativeness.
But when you spot insider buys (code "P") on Form 4, those are often bullish signals (remember Lynch's quote²³). Savvy investors will watch multiple insiders: if several executives buy at the same time, that can be a strong vote of confidence.
Schedule 13D & 13G (Large Shareholders)
Beyond insider trades, SEC rules also target any investor who crosses the 5% ownership threshold of a company's voting stock. Two schedules exist:
Schedule 13D
Known as the "beneficial ownership report," filed by anyone (individual or group) who acquires >5% of a company's shares and has any intent to influence control. Under the updated rules, this must be filed within 5 business days of passing 5%²⁴.
A Schedule 13D discloses the buyer's identity, background, source of funds, purpose (e.g. takeover, proxy fight, strategic alliance), and plans for the company²⁵. Investors pore over 13Ds as potential harbingers of activism or takeovers²⁶.
For example, if a hedge fund suddenly takes 7% of a target and files a 13D saying "we plan to seek board seats," that signals a fight. Conversely, even a passive 5% stake triggers 13D unless the buyer qualifies for the lighter 13G form.
Schedule 13G
This is a shorter form for passive investors (like mutual funds, pension funds, or others who own >5% but aren't trying to control the company). They still must disclose reaching 5%, but the filing omits activist intentions²⁷.
According to SmartAsset, "Schedule 13G is filed when an investor has no intention of influencing or controlling the company"²⁸, so it's a streamlined way to report a big passive stake. For instance, Vanguard or BlackRock routinely file 13Gs for large index positions.
Because 13G filers are passive, their filings tend to lag actual trading – e.g. an institutional buyer might already own 6% for months by the time the 13G shows it. Still, these filings let you track major institutional ownership (e.g. Berkshire Hathaway's 34% stake in Occidental in late 2023²⁹ was reported via Schedule filings).
13D vs. 13G: Key Differences
Comparing 13D vs. 13G is critical: as SmartAsset puts it, "Schedule 13G is designed for passive investors who do not intend to influence or control"³⁰, while 13D is for activists who do. So if you see a 13D (with lots of explanation of strategy), that's usually more "eventful." A 13G, especially from a known mutual fund, often just reflects routine portfolio accumulation.
The deadlines also differ: 13Ds are (recently) due in 5 days³¹, whereas 13G initial reports came much later (and often annual or quarterly)³².
Form 144 (Insider Sales Notice)
Form 144 is often overlooked but can signal an impending flood of stock. This is a notice that an insider or affiliate plans to sell restricted stock. It's not an exact sale report (like Form 4), but it tells the public: "Someone will be selling up to X shares in the next 90 days"³³.
As Investopedia notes, Form 144 "indicates how many potential shares will be offered for sale" after a lock-up or upon plan expiration, which can impact price³⁴.
For example, after a tech IPO, executives and early investors typically sign 180-day lock-ups. When that period ends, they file Form 144 showing how many shares each plans to dump. A large Form 144 can presage selling pressure. Even for non-IPO companies, Form 144 might appear if insiders acquired restricted stock via private placement or drift, and now want to sell.
Form 13F (Institutional Holdings)
Finally, we look at Form 13F. This is not a Form 16/13 Section filing, but an SEC requirement for big money managers. Any investment manager (mutual fund, hedge fund, etc.) with ≥$100 million in US equities must file Form 13F every quarter³⁵.
The filing (due 45 days after quarter-end) lists all the stocks in their portfolio (from an approved list of securities). Think of 13Fs as a delayed "quarterly picture" of the big funds' portfolios.
Why do investors care? The aggregated 13Fs are public and often scoured by retail traders. The hope is to follow "smart money." For instance, after Q1 of 2023 closed, you can read 13Fs of Bridgewater, Renaissance, or Berkshire to see what stocks they added or shed³⁶.
Bloomberg and financial media frequently report "funds buying X, selling Y" based on these filings. (That said, 13Fs have caveats: the data is stale by up to 3 months, and only cover large-cap US equities.)
In summary, Form 13F is a broad signal of institutional interest. According to Investopedia, Congress intended 13F to "provide transparency on the holdings of the nation's biggest investors"³⁷. In practice, small investors might use it as one factor ("Hey, Fund Z owns 10% of this small biopharma").
Putting It All Together
Knowing all these forms gives an edge. A few pointers:
Combine signals: A single Form 4 buy might not mean much, but if that purchase coincides with a new 13D on the company or strong earnings, the signal is stronger. Similarly, multiple insiders buying while large funds (via 13F) increase their stake can reinforce confidence.
Watch timing and context: A cluster of Form 4 purchases by insiders (especially non-rule-based buys) often indicates they're optimistic³⁸. Conversely, large Form 4 sells can be neutralized by notes of 10b5-1 plans³⁹ or company stock sales (like scheduled option exercises). Large Form 144 filings, especially right after lock-ups, usually mean selling pressure rather than insider panic.
Compare Form types: Remember: Schedule 13D vs 13G. Form 4 vs Form 5. A 13G by Vanguard is normal; a 13D by Carl Icahn is news. An insider Form 4 coded "A" (grant) is not the same as "P" or "S". Reading the transaction codes⁴⁰ and footnotes (if any) is important.
Use EDGAR and tools: All these filings are public on the SEC's EDGAR site⁴¹. You can search by company or CIK number. Many third-party sites (like SecForm4.com, Yahoo Finance, Insider Monitor, etc.) aggregate and filter Forms 3/4/5, 13Ds, and even 13Fs⁴². Setting up alerts for insider buys or large stake filings is a common tactic.
Know the limitations: SEC filings report only legal disclosures. Insiders can trade in dark pools (still reportable), or hedge their positions (code "K" swaps). And remember, insiders often sell for routine reasons (taxes, diversification) so every sell isn't a red flag.
As noted, Peter Lynch's famous line⁴³ reminds us that buy-side information tends to be more "honest" bullish signals. But savvy investors still track big sales for market impact – for instance, a CEO dumping millions of shares might depress the stock, even if it's "for the house" or routine.
Key Takeaways
Think beyond Form 4: The full SEC disclosure toolkit includes Forms 3, 4, 5, 144 and Schedules 13D/13G (plus 13F) – each with different triggers and deadlines⁴⁴.
Deadlines matter: Form 3 (10 days after becoming an insider)⁴⁵, Form 4 (2 business days after each trade)⁴⁶, Form 5 (45 days after year-end)⁴⁷, 13D (5 days after hitting 5%)⁴⁸, 13G (usually annual or as scheduled)⁴⁹.
Contextual analysis: Insider buys often signal undervaluation⁵⁰. Sells can be neutral or negative, depending on codes and plans⁵¹. Schedule 13D filers may be activists; 13G filers are usually passive⁵².
Use EDGAR/data tools: All filings are public. Learn to query EDGAR or use specialized sites to aggregate insider trades and ownership filings⁵³. Watch for patterns (multiple insiders buying, new 13D etc.).
By mastering these filings, you'll have a much richer view of insider and big-money movements in the equity markets. As one insider-trading adage goes, insiders might sell for many reasons, but when they buy, they're betting on the company – and often they're right⁵⁴.
Disclaimer: This information is for educational purposes only and should not be considered investment advice. Past performance does not guarantee future results. Always consult with a qualified financial advisor before making investment decisions.
Sources
- SEC filing - Wikipedia
- SEC Filings: Forms You Need To Know - Investopedia
- Updated Investor Bulletin: Insider Transactions and Forms 3, 4, and 5
- Schedules 13D and 13G - Investor.gov
- SEC Form 13F: What It Is, Filing Requirements, and Key Issues
- Sec Form 4 Filing - Prante Gerhard @ Cibus, Inc.
- Schedule 13D: What It Is, How to File, Requirements, Example
- What Is Schedule 13G and Who Has to File It? - SmartAsset
- OXY 13D/13G Filings - OCCIDENTAL PETROLEUM CORP