Start Here · Weigh the Signal
Start with How to Read Insider BuyingHow to Read Insider Buying
A broad field guide to deciding when insider activity deserves attention—and when the filing is more ordinary than the headline.
Learn to read insider activity and SEC filings
Field guides for reading insider activity, SEC filings, and market evidence without outsourcing your judgment.
A filing is evidence, not a verdict. Context decides whether an event matters—and the first useful question is often what weakens it.
Featured · Start here
Build the reading habit before the thesis.
Reading path
Decode the Filing
Start with the document: fields, codes, dates, ownership, plans, and footnotes.
SEC Form 4 Explained
A document-anatomy guide to the fields, tables, footnotes, and dates that turn a filing into usable evidence.
Reviewed Read SEC Form 4 Explained
Form 4 Transaction Codes
A quick-reference desk for the letters that separate a purchase from a grant, exercise, withholding event, gift, or sale.
Reviewed Read Form 4 Transaction Codes
Option Exercise vs. Open-Market Purchase
A filing-mechanics guide to separating option exercises, issuer withholding, and exercise-linked sales from a fresh decision to buy at the market price.
Rule 10b5-1 Explained
A careful guide to adoption, execution, cooling-off periods, modifications, and the limits of inferring motive from a scheduled trade.
Reviewed Read Rule 10b5-1 Explained
Reading path
Weigh the Signal
Compare buying and selling, then test whether several actors form a real pattern.
Insider Buying vs. Selling
A comparison framework for why purchases and sales often carry different information—and why that asymmetry remains a heuristic, not a law.
Reviewed Read Insider Buying vs. Selling
Cluster Insider Buying
A transparent framework for deciding when several insider purchases form a pattern rather than a pile of unrelated filings.
Reviewed Read Cluster Insider Buying
Reading path
The Skeptic’s Desk
Lead with the ordinary explanation and make the apparent signal survive it.
Why Insider Buying Can Mislead
The library’s strongest skeptical guide: start with what would make the apparent signal ordinary, then decide whether anything notable remains.
Reviewed Read Why Insider Buying Can Mislead
Method, not mystique
How Buteon Thinks
Evidence can be notable without being convincing. A careful system keeps that gap visible.
The method surface
What is Buteon?
See how filings, actor context, market reaction, and outcome memory become a structured read—plus what Buteon will not claim or decide for you.
Read how Buteon turns evidence into a read- Evidence
- What the source actually records.
- Notability
- Whether the event deserves closer inspection.
- Conviction
- Whether the wider evidence stack aligns.
- Counter-case
- What weakens, confirms, or invalidates the read.
Case Files · method applied
See the concepts tested against real filings.
The guides teach the mechanics. Case Files preserve Buteon’s historical read, show what supported and weakened it, and separate later follow-up from what was knowable then.
UA / UAABullish · Medium
Prem Watsa's Under Armour Purchase: What Filings Show
A 10% owner buying more with real capital is a different class of evidence from a busy filing week — and even then, Medium confidence was the ceiling.
10 min readReviewed
AMZNNon-actionable · Low
Jeff Bezos and the $4 Billion Amazon Sale Headline: What the SEC Filings Actually Show
The $4.07 billion headline came from a Form 144 notice of a proposed sale, not a completed one. The Form 4 that followed reported 1,209,649 shares actually sold — about $346 million, or roughly 8% of the amount noticed.
8 min readReviewed
TSLANon-actionable · Low
Elon Musk's Tesla Option Exercise: What It Showed
A Form 4 covering more than 300 million Tesla shares contained no open-market trade: an option exercise, a net-share settlement, and restricted stock scheduled to vest in 2028.
9 min readReviewed
SOFIBullish · Low
SoFi CEO Anthony Noto’s Open-Market Purchase: What the Filing Showed
A CEO buying with personal capital is notable, but one isolated purchase does not create high conviction.
7 min readReviewed
NVDAWatching · Low
NVIDIA’s Jensen Huang and a 400,000-Share Transaction: Why the Code Matters
“Disposed” does not automatically mean “sold.” Transaction code G identified a gift, not a market sale.
6 min readReviewed
AMDNon-actionable · Low
AMD CEO Lisa Su’s Stock Sale and a 10b5-1 Plan: What the Filing Showed
A large planned sale under a Rule 10b5-1 program adopted months earlier is not automatically a bearish statement about the current price.
8 min readReviewed
GOOGLBearish · Low
An Alphabet Insider “Cluster”: What Five Filings Actually Showed
A cluster is only as strong as its independence and transaction codes; five names in a filing window can still reflect mostly routine mechanics.
10 min readReviewed
Buteon Research · evidence synthesis
Research NoteSee the method applied to public evidence.
Research Notes separate observations, estimates, forecasts, and uncertainty without implying that Buteon monitored the subject live.
Evidence reviewed through 13 August 2026
Read the Research Note SpaceX stock: how much of tomorrow is already in the price?
SpaceX’s valuation is already a forecast.
Editorial standard
How this library works
Primary sources first
SEC filings, official instructions, Investor.gov, and current rule material are preferred over summaries.
Educational by design
The guides explain evidence and uncertainty. They do not provide investment advice or buy/sell recommendations.
Visible review dates
Every guide carries a publication date, last-reviewed date, organizational byline, and review note.
Uncertainty stated
SEC-defined fields are separated from interpretation, and “we do not know” remains an acceptable answer.
AI-assisted explanation, evidence first
Where available, Buteon's optional narrative brief explains deterministic filing intelligence. It does not change the verdict or replace the source.
No borrowed certainty
No performance promises, invented expertise, or competitor claims are used to make the library sound more authoritative.
Free filing tool
Form 4 Filing Reality Check
Look up a transaction code, understand what it mechanically reports, and see which details should be checked before interpretation.
Open the Form 4 decoderOpen beta
Use the research tool when you want the context assembled.
Buteon is building a disciplined layer around insider filings and related evidence. The library remains useful on its own; the product is in open beta with a free plan.
Buteon is a research tool. It does not provide investment advice or buy/sell recommendations.