Section 16(b) is the rule in the Section 16 family that operates without fault, and that is what makes it dangerous to a well-meaning executive. It lets a company recover any profit a reporting person realizes from a purchase and sale, or a sale and purchase, of the company's equity within any period of less than six months. There is no state-of-mind element. The person need not have held inside information, need not have intended anything, need not even have made money on the position overall. If two opposite-way transactions match inside the window, there is disgorgeable profit. The only reliable defense is not tripping it.
What the rule recovers
Section 16(b) reaches directors, designated officers and beneficial owners of more than 10% of a registered class of equity. The recovery runs to the issuer, and if the issuer will not pursue it, a shareholder may sue derivatively on the company's behalf, which is how many of these claims actually arrive, often from plaintiff's firms that monitor Section 16 filings precisely for matchable pairs. The public filings are the surveillance tool used against the filer.
For directors and officers, a matchable transaction on one end is enough. A sale is recoverable against any purchase within six months on either side of it. For 10% holders the rule is stricter in one respect. The person must be over the threshold at both ends of the pair. That asymmetry catches people out. A director does not get the 10% holder's both-ends protection.
How the profit is calculated
This calculation is not accounting profit, and this is the part that surprises people. Courts do not net your trades or apply first-in-first-out. They match to maximize the recoverable amount, pairing the lowest purchase price against the highest sale price within the window, then the next pair, and so on (the approach set in Smolowe v. Delendo Corp.). The consequence is that a reporting person who lost money across a series of trades can still owe "profit" under Section 16(b), because the rule pairs the best buy against the best sell regardless of what actually happened to the portfolio.
That counter-intuitive arithmetic is the whole reason the six-month calendar is watched as closely as the filing deadlines. The liability is mechanical, so the control has to be preventive.
The six-month calendar
Operational discipline here is simple to state and easy to lose. For every reportable transaction, know what opposite-way transactions sit within the six months before and after it. A purchase in January and a sale in May are a matchable pair. A sale in March and a purchase in July are too. Grants, exercises, open-market trades and plan executions all enter the calendar. Watching one end of a person's activity without the other is how a matchable pair slips through.
The exemptions
Not every transaction counts. Rule 16b-3 exempts many transactions with the issuer (grants, awards and certain tax-withholding dispositions) provided the conditions are met, typically approval by the board or a qualifying committee, approval by shareholders, or a holding period. Rule 16b-6 governs how derivative securities are treated, and other rules exempt transactions in mergers and reclassifications. Bona fide gifts are generally not purchases or sales. These exemptions are conditional, not automatic. The condition, the right approval, properly minuted, is what carries the exemption. A condition you can produce is a defense. One you have to reconstruct is a gap.
Where the rule sits
Section 16(b) is a prophylactic disgorgement rule, not an insider-trading prohibition. It is entirely separate from the Section 10(b) and Rule 10b-5 anti-fraud regime. A trade can be cleared through pre-clearance, made with no MNPI, and lawful in every other respect, and still create Section 16(b) liability because it matched. Keep the two ideas apart in any policy. Clearance addresses trading on information. The six-month calendar addresses matching. This piece sits alongside "Section 16 mechanics for Forms 3, 4 and 5" and "Beneficial ownership under Section 16," which cover coverage and the forms.
InsiderList captures each reporting person's transactions against a reconciled ledger and surfaces the opposite-way transactions inside the six-month window, so a matchable pair is visible before a trade is placed rather than after a filing exposes it. Whether a transaction is exempt, and whether a given pair creates liability, are determinations your counsel makes.
See the six-month calendar watched per reporting person before a trade is placed. 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.