Stock: Insider Transactions

A practical guide to using SEC Form 4 insider buy/sell activity as a sentiment signal alongside a price series.

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Overview

This data source exposes three scalar metrics per issuer, assembled directly from SEC Form 4 filings — the disclosure officers, directors, and 10%+ owners ("insiders") must file whenever they trade their own company's stock:

• inbv — Net dollar value of open-market insider buys minus sells
• ibc — Count of open-market insider buy legs
• isc — Count of open-market insider sell legs

Why this matters: insiders have the best information available about their own company, and SEC rules force their trades into the public record. A cluster of buying by multiple insiders is a widely watched bullish tell; heavy, concentrated selling is a weaker signal on its own (executives sell routinely for diversification, tax, and compensation reasons) but becomes notable when it clusters across several insiders at once.

• Update cadence: daily (1d), but the series is genuinely sparse — most trading days produce no filings for a given issuer.
• Coverage: 48 issuers — NVIDIA (NVDA), Apple (AAPL), Microsoft (MSFT), Amazon (AMZN), Tesla (TSLA), Berkshire Hathaway (BRK.B), IonQ (IONQ), Micron (MU), SpaceX (SPCX), Sandisk (SNDK), Advanced Micro Devices (AMD), Meta (META), Alphabet (GOOGL), Broadcom (AVGO), Intel (INTC), Palantir (PLTR), Oracle (ORCL), TSMC (TSM), Marvell (MRVL), Netflix (NFLX), Eli Lilly (LLY), Applied Materials (AMAT), Strategy (MSTR), Western Digital (WDC), JPMorgan Chase (JPM), Nebius (NBIS), Walmart (WMT), Robinhood (HOOD), CoreWeave (CRWV), Lam Research (LRCX), UnitedHealth (UNH), Seagate (STX), Qualcomm (QCOM), Bloom Energy (BE), Visa (V), Dell (DELL), Costco (COST), ServiceNow (NOW), Caterpillar (CAT), Coinbase (COIN), Cisco (CSCO), IREN (IREN), Bank of America (BAC), Johnson & Johnson (JNJ), Chevron (CVX), AbbVie (ABBV), Coca-Cola (KO), Ford (F).
• History: back to 2007-01-01, or the issuer's first Form 4 where that came later: V 2008-03-20, TSLA 2010-07-02, META 2012-05-17, NOW 2012-06-29, ABBV 2012-12-14, GOOGL 2015-10-08, DELL 2016-09-07, AVGO 2018-04-06, BE 2018-07-26, PLTR 2020-10-02, COIN 2021-04-05, MRVL 2021-04-21, HOOD 2021-07-30, IONQ 2021-10-04, SNDK 2025-02-14, CRWV 2025-03-31, IREN 2025-07-03, TSM 2026-03-24, NBIS 2026-04-01, SPCX 2026-06-17.
• Source: SEC EDGAR Form 4 filings (public domain; https://www.sec.gov/edgar).

Metrics Summary

Field	Description	Units	Notes
inbv	Net buy value: sum(buy $) − sum(sell$) for the day	$	Open-market transactions only (Form 4 codes P and S)
ibc	Count of buy (P) legs for the day	count
isc	Count of sell (S) legs for the day	count

Note: values are pre-summed per (issuer, filing date) before publishing — a day with three separate buy filings for the same issuer produces one datapoint, not three.

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What Is a Form 4?

Section 16 of the Securities Exchange Act requires officers, directors, and beneficial owners of more than 10% of a company's stock to report changes in their holdings on Form 4. The filing deadline is two business days after the transaction, one of the tightest disclosure windows in securities law.

flowchart LR
    A[Insider Executes Trade] --> B[2 Business Day Deadline]
    B --> C[Form 4 Filed with SEC EDGAR]
    C --> D[Transaction Legs Parsed]
    D --> E{Code P or S?}
    E -->|P Buy| F1[Add to ibc, inbv]
    E -->|S Sell| F2[Add to isc, subtract from inbv]
    F1 --> G[Pre-summed per Issuer per Filing Date]
    F2 --> G

Filing-Date Axis (Adjudicated)

A single Form 4 can report multiple transactions with different trade dates, and the same trade can occasionally appear across amended filings. To keep the series exactly recomputable from the public index — the same guarantee EDGAR fundamentals give you — this source keys every datapoint to filing date, not transaction date. The economics can lag the actual trade by up to two business days, but filing date is the only axis that is unambiguous and stable no matter how a filing is later amended.

Amendments (Form 4/A) are excluded in this version. There is no reliable machine link from an amendment back to the specific transaction it corrects, and amendments are rare (roughly 1 in 588 filings in a sampled issuer's history). An investor relying on this series for a specific trade should still cross-reference the primary filing on EDGAR.

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Buy/Sell Semantics

Only open-market purchase and sale transactions are counted — Form 4 transaction codes P (open-market buy) and S (open-market sale). Everything else on a Form 4 is excluded: option exercises, grants, gifts, and other non-open-market codes carry different economics and would distort a "did an insider put real money in or take it out" signal.

flowchart TD
    T[Form 4 Transaction Leg] --> C{Transaction Code}
    C -->|P: Open-Market Buy| Y1[Counted: +value to inbv, +1 to ibc]
    C -->|S: Open-Market Sale| Y2[Counted: -value to inbv, +1 to isc]
    C -->|Other e.g. option exercise, grant, gift| N[Excluded]

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Sparsity Is Expected

This is the sparsest series on the platform by design, not by ingestion failure:

• Sell legs (S) dominate. Compensation-linked selling (10b5-1 plans, tax withholding on vesting) is routine; open-market buys are comparatively rare and therefore more informative when they happen.
• Most days have zero filings for a given issuer — insider trading activity clusters around earnings windows and vesting schedules, not a fixed calendar tick. Do not assume a daily datapoint; gate downstream logic on the datapoint actually changing.
• A long gap in inbv/ibc/isc is normal behavior for this source, not a data outage.

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Practical Examples (Illustrative Rules)

• If ibc > 0 for 2+ distinct filing dates within a 30-day window AND inbv is positive → cluster-buying signal, a stronger bullish tell than a single isolated purchase.
• If isc spikes sharply above its trailing average without a corresponding ibc → check for a scheduled 10b5-1 sale window before reading it as bearish.
• Combine with Stock: Fundamentals earnings-release timing — insider buying shortly before a filing is restricted by blackout policies at most companies, so a buy just after an earnings release carries more weight than one mid-quarter.

flowchart TD
    S[Daily Check] --> R1{ibc > 0 on 2+ Recent Dates?}
    R1 -->|Yes| R2{inbv Net Positive?}
    R2 -->|Yes| T1[Flag: Cluster Buying]
    R2 -->|No| T2[Neutral]
    R1 -->|No| T3{isc Spike Without ibc?}
    T3 -->|Yes| T4[Check for Scheduled Sale Window]
    T3 -->|No| T2

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Practical Notes

• Coverage is wider than Stock: Fundamentals': insider dollar values do not depend on share class, so Berkshire Hathaway (BRK.B) is served here, and so are TSMC (TSM) and SpaceX (SPCX), whose filings yield no fundamentals. SK hynix (SKHY) and ASML Holding (ASML) file no Form 4, and ExxonMobil's (XOM) insiders now file under a 2026 holding company that has filed none yet.
• Backfill starts 2007-01-01 — earlier than the fundamentals ~2009 XBRL cutoff, since Form 4's electronic filing requirement predates the XBRL structured-data mandate.
• Form 4/A amendments are not reflected; treat this series as the as-originally-filed record.
• Data is public domain (SEC EDGAR); no redistribution restrictions, but always verify a specific transaction against the primary filing before relying on it for a live decision.