Form 4 Insider Buying While Activists File: A 1,079-Transaction Database Study

Of the 60 most recent Schedule 13D filings in the 13dwatch database, six (10%) coincide with any insider Form 4 transaction within 90 days on the same issuer. None of the six is an open-market purchase (transaction code P). The "smart-money cluster" pattern — activist files, management buys — shows up at a base rate near zero in current data.

What was measured

The 13dwatch pipeline holds 1,079 Form 4 insider transactions and 17,568 activist filings as of 2026-05-05, queryable at /api/health. For the 60 most recent activist filings (dated 2026-04-03 to 2026-04-28), the worker joins each filing to insider transactions on the same issuer (issuer_cik match) within a trailing 90-day window. The full join is exposed at /api/feed; per-filing detail with a 365-day insider window is at /api/filing/{accession_number}.

A Schedule 13D is a U.S. Securities and Exchange Commission (SEC) filing required of any beneficial owner who acquires more than 5% of a registered class of equity with control intent (17 CFR 240.13d-1). A Form 4 is the Section 16(a) statement of changes in beneficial ownership filed by every officer, director, and 10%+ owner within 2 business days of any qualifying transaction (15 U.S.C. § 78p(a)). The two filings overlap when the same actor crosses both thresholds, and when an activist 13D filer's target also has insiders trading on its own register.

The headline number

Source: /api/feed on 2026-05-05. Filings dated 2026-04-03 through 2026-04-28.

Ten-percent overlap looks like a meaningful signal until the codes are decoded.

Why "10% overlap" misleads

The Form 4 instructions (SEC Form 4, Table II, p. 4) define discrete transaction codes. Only code P is an unambiguous open-market or private discretionary purchase. The codes most commonly mistaken for "insider buying" are mechanical:

• A — Grant or award under Rule 16b-3 (typically RSU vesting or restricted-stock awards).
• D — Disposition to the issuer under Rule 16b-3 (often share withholding for tax).
• F — Payment of exercise price or tax liability by share withholding.
• G — Bona fide gift.
• J — Other acquisition or disposition (a catch-all that includes derivative settlements, broker-account migrations, and trust transfers).
• M — Exercise or conversion of a derivative.

A code-A row tells the reader an officer received equity compensation. It does not tell the reader the officer chose to spend cash on stock. Aggregators that count any "acquisition" as a buy are, in practice, counting payroll.

Of the six 13D filings in the sample with any insider transaction in the 90-day window, the code mix is:

Source: /api/filing/{accession_number}, 365-day insider window per filing.

Zero P-code rows. The ostensible 10% overlap is, on inspection, 2 open-market sales (Docler Holding's filers selling Playboy stock), 2 equity awards, and 2 code-J other-disposition rows.

Reporting overlap is not signal

Four of the six matches are the same legal entity reporting through two compliance channels. Joseph Davy filed both the 13D on Banzai International and a Form 4 award on the same day. Carlson Capital, Luminus Management, and Bank of America each filed both their Schedule 13D and a Form 4 on the issuers they were targeting — because as 5%+ holders, they are simultaneously Section 13(d) and Section 16(a) reporters.

This is a known artifact of cross-sectional database joins. The valuable signal — independent management of the issuer choosing to buy alongside an outside activist — is filtered out by removing rows where Form 4 filer_name == 13D filer_name (or where is_ten_percent_owner is true and director/officer flags are false). Apply that filter, and the sample yields 2 management Form 4s in 26 days of activist filings: the 2 open-market sales at Playboy. Both are dispositions, not acquisitions.

When the cluster pattern actually matters

The "follow the smart money" thesis has a real academic foundation. Brav, Jiang, Partnoy and Thomas (2008) document approximately +7% abnormal returns in the 20-day window around a hedge-fund activist 13D announcement, with no reversal over the following year. Cohen, Malloy and Pomorski (2012) show that "opportunistic" insider trades — those by insiders without a routine pattern — generate significant long-short alpha. The intersection of these effects, when it shows up, is high-conviction.

The empirical question is how often it shows up. The current 26-day slice says: not in the noisy way the term "smart-money cluster" implies. The pattern is rare enough that retail aggregators systematically labeling code-A awards as "insider buys" are producing false positives at scale.

A serious cross-source study would extend the window backwards through the full 17,568-filing history, slice by issuer market capitalization, and exclude all rows where the Form 4 filer is the same legal entity as the 13D filer. That work is the next data study in this series.

How to spot a real cluster yourself

The schema is public and the join is reproducible:

curl -s https://13dwatch.com/api/feed | jq '
  .filings[]
  | select(.insider_activity != null)
  | { filing_date, filer: .filer_name, issuer: .issuer_name,
      ticker: .issuer_ticker,
      buys: .insider_activity.buys,
      sells: .insider_activity.sells,
      buy_dollars: .insider_activity.buy_dollars }'

For each filing flagged with insider_activity, fetch the full 365-day transaction detail and filter for transaction_code == "P" where filer_name != activist filer_name. Any row that survives is a candidate management-side cluster setup worth a closer read.

What this means for hedge fund managers and RIAs

The sub-$500M fund or RIA reading 13D filings as a top-of-funnel idea source should:

1. Treat any "insider buying" claim from a third-party aggregator as suspect until the transaction codes are inspected.
2. Use the 13dwatch feed (or the SEC EDGAR Form 4 raw filings, free at sec.gov/cgi-bin/browse-edgar) to confirm any cluster claim is built on code-P rows.
3. Recognize that the absence of insider buying alongside an activist 13D is the base case, not a contrarian indicator. The presence of a code-P insider buy by a non-activist officer is the signal — and it's rare.

The pattern most worth tracking is asymmetric: activist 13D + non-activist insider open-market buy + rising short interest. That combination is what the 13dwatch live feed is built to surface. As of the latest snapshot, the count is zero. When it becomes one, that filing is worth 20 minutes of an analyst's time.

The live cross-source feed is at 13dwatch.com. Pilot access is $1,500/month — request a 20-minute walkthrough.

Frequently asked questions

What is a Form 4 filing?

A Form 4 is a U.S. Securities and Exchange Commission (SEC) statement of changes in beneficial ownership, required of every officer, director, and 10%+ stockholder of a registered issuer under Section 16(a) of the Securities Exchange Act of 1934. It must be filed within 2 business days of any reportable transaction in the issuer's equity. Filings are public on EDGAR the same day.

Does an activist 13D filing usually mean insiders are also buying?

No. In the 60 most recent Schedule 13D filings indexed by 13dwatch, six show any insider Form 4 activity in the prior 90 days, and zero show an open-market insider purchase (transaction code P). The "activist plus insiders" cluster pattern is rare in current data. Most Form 4 rows that look like overlap are equity awards, dispositions, or the activist itself reporting through Section 16.

What do Form 4 transaction codes mean?

The SEC defines discrete codes in Form 4 Table II. The signal-bearing code is P (open-market or private discretionary purchase). Code S is a sale. Codes A (award), D (disposition to issuer), F (tax withholding), G (gift), J (other), and M (derivative exercise) are mechanical and do not represent a discretionary buy decision. Aggregators that count any "acquisition" as a buy include codes A, J, and M alongside P, which inflates the apparent insider-buying signal.

What is the difference between Schedule 13D and Form 4?

Schedule 13D is filed by any beneficial owner who acquires more than 5% of a class of registered equity with control intent (17 CFR 240.13d-1), within 5 business days of crossing the threshold. Form 4 is filed by every Section 16 insider (officer, director, 10%+ owner) within 2 business days of any change in beneficial ownership. A 5%+ activist who is also a director triggers both. See 13D vs 13G vs 13F.

How can I see Form 4 filings alongside Schedule 13D filings myself?

The 13dwatch /api/feed endpoint returns the 60 most recent activist filings with the 90-day insider join already computed. The per-filing endpoint /api/filing/{accession_number} returns a 365-day insider window. Both are public and require no authentication. The SEC EDGAR full-text search at efts.sec.gov provides the raw filings.

Is insider buying alongside an activist a reliable trade signal?

The academic literature (Brav, Jiang, Partnoy and Thomas, 2008; Cohen, Malloy and Pomorski, 2012) supports the hypothesis that activist 13D announcements and opportunistic insider purchases each carry abnormal-return signal in isolation. The combined pattern — an activist 13D plus a non-activist code-P insider purchase plus rising short interest — is rarer than retail commentary implies, and worth a closer read when it occurs. This is research, not investment advice.

Methodology and limitations: This study uses the 60 most recent Schedule 13D and 13D/A filings exposed at /api/feed on 2026-05-05, dated 2026-04-03 through 2026-04-28. The insider-transaction join uses a 90-day trailing window per the worker's INSIDER_DAYS constant. The 13dwatch insider_transactions table contains 1,079 rows as of the same timestamp (/api/health); per the public worker source, approximately 10% of those rows have populated issuer_cik, which caps join recall. The directional finding (zero code-P matches) is robust to that ceiling: a 10× recall multiplier on six joined rows would still leave the discretionary-buy count at single digits in a 60-filing slice. The reference to a 928-transaction count in earlier 13dwatch materials reflects the database state in April 2026; the pipeline ingests new Form 4s continuously, and the count grows. Research, not investment advice. Long Street Consulting LLC.