Regulation

Material Non-Public Information (MNPI)

By InsiderAlpha Research · Reviewed August 3, 2026

Information that is material to a reasonable investor and not yet public, central to insider-trading analysis but not determinable from Form 4 alone.

Definition

Material nonpublic information is information that has not been disseminated publicly and that a reasonable investor would likely consider important in an investment decision or that could significantly alter the total mix of available information. Materiality and public availability depend on facts and context.

Material nonpublic information is a legal and factual concept, not a dataset label. Form 4 can establish who reported a transaction, what was reported, and when; it cannot establish what the person knew or whether liability exists.

What Counts as Material

Information is material when a reasonable investor would consider it important in making a buy, sell, or hold decision. Examples include earnings surprises, merger negotiations, regulatory decisions, major customer losses, cybersecurity breaches, or unreleased clinical trial results.

The information does not need to guarantee a price move. It only needs to be important enough that disclosure would reasonably alter investor behavior.

Why Form 4 Still Matters

Form 4 filings do not prove whether an insider had MNPI. They disclose the trade after it happened. Analysts use them as a public audit trail: timing, trade size, transaction type, and proximity to material announcements can all raise or lower concern.

Rule 10b5-1 plans exist partly to reduce this risk by scheduling trades in advance, when the insider is not supposed to possess MNPI.

What the Dataset Can and Cannot Show

InsiderAlpha can preserve transaction date, filing date, acceptance time, code, value, ownership nature, plan language in available footnotes, and accession lineage. Those fields support chronology and reproducibility.

They do not determine knowledge, materiality, public dissemination, duty, scienter, tipping, or eligibility for a defense. Editorial copy should describe proximity to an event rather than declaring a trade legal or illegal.

MNPI vs Public Information

InformationStatusExample
Draft earnings missMNPINot yet disclosed and likely material to investors.
Published 10-KPublicAlready available through SEC filings.
Signed but undisclosed mergerMNPIHighly material if not yet announced.

Primary Sources & Filing References

Why it matters for Whale Tracking

MNPI defines a legal risk boundary, but a Form 4 is a disclosure record rather than a finding about legality. Transaction timing can support research questions; it cannot establish what the trader knew, whether information was material, whether it was public, or whether a duty or defense applied.

Technical Nuance

A trade before an announcement is not automatically unlawful, and a trade after an announcement does not prove that every material fact was public. Rule 10b5-1, duties of trust or confidence, tender-offer rules, tipping, scienter, and the manner of dissemination can all matter.

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Real-World Example

"If an officer trades near a product announcement, the defensible dataset statement is limited to the transaction and disclosure chronology. Determining MNPI possession or liability requires evidence beyond the filing."

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Material Non-Public Information (MNPI) — Frequently Asked Questions

>Does a Form 4 prove insider trading happened illegally?

No. Form 4 is a disclosure document. It reports trades by insiders but does not prove the insider traded while holding MNPI.

>Why do 10b5-1 plans matter for MNPI?

They can provide an affirmative defense because trades are scheduled in advance when the insider is not supposed to possess MNPI.

>What makes information material?

Information is material if a reasonable investor would likely consider it important in deciding whether to buy, sell, or hold the security.