Updated May 10, 2026 · 640 articles
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Educational guides about 13F filings, insider trading, institutional investing, and how to track smart money moves.
10b5-1 Plan Footnotes on Form 4: Reading Guide
What the Rule 10b5-1 plan footnote on a Form 4 actually contains, the four checks to run on every plan-footnoted sale, and the safe editorial framing when the footnote is missing.
Sarah MitchellForeign-Domiciled Passive Sleeves: Reading Their 13Fs
How to identify a foreign-domiciled passive sleeve from a 13F holdings table — three structural tells, why the misread matters, and a worked example from a UK Vanguard filer.
Sarah Mitchell13D vs 13G Filings: What Active vs Passive Intent Really Means
Both Schedule 13D and 13G disclose 5%+ ownership, but they signal opposite things about what the filer intends to do. Three current examples — Sanders Capital, Micron, and the Stryker family — show why the distinction is doing real interpretive work.
Sarah MitchellForm 4 Transaction Codes: How to Read S, G, M, F, and 10b5-1
How to read a Form 4 transaction code without falling into the most common SEC EDGAR trap — distinguishing open-market sales from gifts, plan-driven executions from discretionary trades, and Table I from Table II ownership.
Sarah MitchellSchedule 13G/A Exit Filings: Real Exit or Reporting Move?
How to read a Schedule 13G/A that reports 0.000% ownership without falling into the most common SEC EDGAR trap — distinguishing a real liquidation from a passive-complex reporting reorganization.
Sarah MitchellReading Family Foundation 13Fs: When an Endowment Anchors
The Lilly Endowment holds $84.5B of LLY. Foundations like this anchor the holder file with concentrations no asset manager can match — and they file 13Fs. Reading their distinct flow logic separates structural ownership from active conviction.
Sarah MitchellReading Form 4 P-Codes: When Insiders Actually Buy
S-codes and M-codes dominate Form 4 reading because they outnumber other types 50:1. But the P-code — open-market purchase — is the highest-signal individual transaction in the entire SEC insider tape. Most investors never look for it. They should.
Sarah MitchellReading IPO Lockup Expirations: When Form 4 Hits the Tape
An IPO lockup is the contractual agreement that prevents pre-IPO shareholders from selling for 90-180 days after listing. When the lockup expires, the Form 4 tape gets noisy. Reading the calendar plus the holder file lets you separate mechanical insider sales from conviction signal.
Sarah MitchellReading 13G to 13D Conversions: Passive-to-Activist Flips
The most informative single signal in beneficial-ownership filings is when an investor converts a previously-13G position to a 13D filing. The conversion is the SEC-required acknowledgment that intent has changed from passive to active.
Sarah MitchellDetecting 10b5-1 Plan Execution: VWAP Signature Decoded
Most CEO Form 4 sales are 10b5-1 plan-driven, not discretionary view-driven exits. Reading the VWAP execution signature is the cleanest way to distinguish plan execution from genuine position reduction.
Sarah MitchellReading Multi-Class Form 4: Table I vs Table II Decoded
Form 4 Table I shows direct holdings; Table II shows derivative securities (Class B, options, RSUs in vesting, family trusts). Reading dual-class structures correctly is the single highest-leverage skill in interpreting executive insider filings.
Sarah MitchellWhat Form 13F Doesn't Capture: Blind Spots Decoded
Form 13F is the foundation of institutional ownership analysis — but it has structural blind spots. Shorts, derivatives, foreign equities, and the 45-day reporting lag all create gaps that reading 13F alone will miss.
Sarah MitchellMulti-Brand Asset Manager 13Fs: Franklin, BlackRock, Capital
Multi-brand asset managers aggregate distinct portfolio managers and investment philosophies into a single 13F. Reading aggregator filings requires segmenting tiers by brand and weighting cross-brand confluence as the strongest conviction signal.
Sarah MitchellReading Form 4 M-Codes: Cashless Exercise Plans Decoded
The M+S transaction sequence is the most common Form 4 pattern among S&P 500 CEOs. Reading it correctly distinguishes 10b5-1 cashless exercise plans from discretionary view-driven exits.
Sarah MitchellCross-Border Sovereign Allocators in US 13Fs: Reading the Tail
Norges Bank holds $935B in US equities. CPPIB holds $149B. Swiss National Bank holds $168B. The cross-border sovereign allocator tail in any US equity's 13F file is one of the most underused signals in institutional flow analysis.
Sarah MitchellWhy Market-Maker 13F Holdings Are Not Conviction
Susquehanna reports $4.4B of COIN. Jane Street reports $3.5B. Citadel Securities reports tens of billions across the market. None of it is institutional conviction. Here's what market-maker 13F notional really represents.
Sarah MitchellReading Custody-Bank 13F Filings: BNY Mellon & State Street
BNY Mellon's $568B 13F and State Street's $2.98T are not what they look like. Custody banks file 13Fs based on intermediary asset positions, not portfolio manager discretion. Here's how to read them.
Sarah Mitchell13G Threshold Crossings vs 13D Activist Filings: A Reading Guide
13G threshold crossings and 13D activist filings both disclose 5%+ beneficial ownership, but they signal completely different intent. Learn what each tells you and how to spot the difference in seconds.
Sarah MitchellHealthcare Specialist vs Generalist 13F: Reading FDA Catalysts
FDA catalyst-driven equities have layered holder structures: specialist healthcare managers, generalist mutual funds, market makers, and post-confirmation cross-border allocators. Learn how to identify each in 13F data.
Sarah MitchellReading Merger-Arb Holders in 13F Data: Pentwater, Sessa & Co.
Merger-arb specialists are visible in 13F filings — but they look very different from long-only conviction holders. Learn how to identify Pentwater, Sessa, and similar event-driven names, and what their position size really tells you.
Sarah Mitchell