Introduction
Material non-public information is the thing insider trading law is built around, and the insider list is how a company tracks who holds it. These answers cover the recurring questions, including the one US issuers ask most, whether they have to keep a list at all. For the fuller treatment, read "MNPI handling, who's inside, when, and proving it" and "Insider lists for US issuers without a MAR mandate".
What is material non-public information?
Information is material if there is a substantial likelihood that a reasonable investor would consider it important in making an investment decision, or that it would significantly alter the total mix of available information. It is non-public until it has been disseminated broadly to the market and the market has had time to absorb it. Both halves must be true. Public-but-immaterial and material-but-public information are outside the prohibition.
What kinds of information are usually material?
Earnings and financial results, mergers and acquisitions, major contracts or their loss, changes in senior management, significant litigation or regulatory action, a pending securities offering, a data breach or cybersecurity incident, and dividend or buyback decisions. Materiality is contextual, not a fixed list, and a development that is trivial for one company can move the market for another. The safe posture is to treat a close case as material.
When does information stop being non-public?
When it has been disclosed through a method reasonably designed to reach the market, such as a Form 8-K, a widely disseminated release, or a public earnings call, and enough time has passed for the market to absorb it. A single conversation, a selective briefing, or a rumour circulating among a few people does not make information public. Being technically findable is not the same as having been disseminated.
Does US law require an issuer to keep an insider list?
No. Unlike the EU Market Abuse Regulation, which mandates a formal insider list with prescribed fields, US law imposes no general obligation to maintain one. What it imposes is liability for trading or tipping on MNPI and, in enforcement, an expectation that a company can show who had access to what and when. Most well-run US issuers keep an access record by choice, because it is the evidence the law's enforcement assumes.
If it is not mandated, why keep one?
Because the record is the defense. When a regulator asks who knew about a development before it was public, the answer needs to exist as a contemporaneous list, not be assembled from memory and email after the fact. An access record also drives the controls that prevent a problem, namely who gets a blackout, who needs pre-clearance, and who is restricted around a deal. The list is the courtesy. The record is the point.
Who goes on the access record?
Everyone with access to a defined piece of MNPI, meaning the deal team, the executives briefed, outside counsel, bankers, auditors and advisers, and the support staff who touched the documents. The record is per matter. It captures who was brought inside a specific piece of information, when, and when they came off. A generic list of senior people is not the same as a record of who was inside a given matter.
How is an MNPI matter opened and closed?
A matter opens when a specific piece of material information arises and a defined group is brought inside it, such as a deal, a restatement, or an incident. The record captures each person's inside date. It closes when the information is public or dead, and each person's exit is recorded. The discipline is in the dates. An access record with reliable in and out timestamps is what makes the later question answerable.
What is the difference between a watch list and a restricted list?
A watch list is confidential, the names of securities the compliance team monitors because the firm may hold MNPI, used to surveil activity without signalling anything. A restricted list is enforced, so trading in the named securities is blocked or requires clearance, and its existence is generally known to affected people. Both are controls layered on the MNPI record. They answer different questions and are kept separately.
How does the access record connect to trading controls?
It feeds them. The people inside a matter are the people who should be under a blackout or a pre-clearance requirement for the affected security, and the record is what tells the controls whom to catch. A list that sits in a drawer proves who knew but stops nothing. A list wired to the blackout and clearance controls both proves access and prevents the trade. The value is in the connection.
What has to be provable after the fact?
Who had access to a specific piece of MNPI, from when to when, and what trading controls applied to them during that window. If those facts are captured as they happen, the answer to an enforcement inquiry is a report. If they are not, the answer is a reconstruction, and reconstruction is exactly what surveillance-driven enforcement is built to test.
InsiderList maintains the MNPI access record per matter, with inside and outside dates per person, and connects it to the blackout and pre-clearance controls that act on the same population, so the record both proves access and drives enforcement, without being rebuilt from memory.
See the access record that both proves who knew and stops the trade. Book a demo with our team.
InsiderList is insider trading compliance software used by companies in the UK, Europe, the USA and the UAE. This article is for general information and does not constitute legal advice. For advice on your situation, consult qualified US securities counsel.
