The Short-Swing Profit Rule

The short version

Section 16(b) of the Securities Exchange Act of 1934 says that if a company insider buys and sells (or sells and buys) the company’s stock within less than six months, any profit belongs to the company. The company can sue to recover it, and if it does not, any shareholder can sue on the company’s behalf.

The rule is blunt on purpose. It does not matter whether the insider used secret information, meant no harm or simply forgot about an earlier trade. If the trades fall inside the window and can be matched at a profit, the money goes back to the company. Lawyers call this “disgorgement.”

Why the rule exists

Congress wrote Section 16 in 1934, after the stock market crash, when insiders trading on their own companies’ news was a widely criticized practice. Proving that someone actually used inside information is hard. Section 16(b) avoids that problem by taking the profit out of quick round trips altogether, whatever the reason for them. The statute itself says the purpose is “preventing the unfair use of information” an insider may have obtained through their position.

Who is covered

The rule applies to the same people who file Forms 3, 4 and 5 under Section 16(a):

• Directors of the company.
• Officers, meaning the president, principal financial and accounting officers, heads of major business units and others with policy-making roles.
• Owners of more than 10% of a class of the company’s registered equity.

For 10% owners there is an extra condition. The statute does not cover a transaction where the person was not a 10% owner at the time of both the purchase and the sale. In a 1976 case, Foremost-McKesson v. Provident Securities, the Supreme Court held that in a purchase followed by a sale, the investor must already be a 10% owner before the purchase. The purchase that first pushes someone over 10% does not count.

Directors and officers have no such carve-out. A director’s trades are covered from the day they join the board, and trades shortly after leaving can still be matched against trades made while they served.

Our guide to Form 3, Form 4 and Form 5 explains these categories in more detail.

How the six-month window works

The statute covers any purchase and sale, or any sale and purchase, “within any period of less than six months.” Some points that surprise people:

• Order does not matter. Selling first and buying back cheaper within six months produces a recoverable profit, just as buying and then selling higher does.
• Any pair counts. Each purchase can be matched against any sale within the window. The trades do not have to involve the same shares.
• Intent does not matter. Liability is strict. The insider does not have to have had inside information.
• Losses elsewhere do not offset. Courts have long matched the lowest-priced purchase against the highest-priced sale within the period, then the next lowest against the next highest, and so on, ignoring pairs that would show a loss. This method traces back to a 1943 federal appeals court decision, Smolowe v. Delendo Corp. It means an insider can owe money to the company even if they lost money overall on their trades.

Derivatives count too. Buying call options, for example, can be treated as a purchase of the underlying stock, and SEC rules set out how options and similar instruments are matched.

A simple example

Suppose a director makes these trades in her company’s stock:

• January 10: buys 1,000 shares at $50.
• March 1: sells 1,000 shares at $40.
• April 15: buys 1,000 shares at $30.
• May 20: sells 1,000 shares at $45.

Over the whole period she lost $10,000 on the first round trip and made $15,000 on the second, for a net gain of $5,000. But under the lowest-in, highest-out method, the lowest purchase ($30 in April) is matched with the highest sale ($45 in May), a $15,000 profit. The next pair, the $50 purchase and the $40 sale, shows a loss and is ignored. She could be required to pay the company $15,000, more than she made overall.

This is a simplified illustration of the matching method. Real cases involve exemptions and detailed calculations.

Important exemptions

Not every transaction counts as a purchase or sale for Section 16(b). The most important is Rule 16b-3, which exempts many transactions between the company and its own directors and officers, such as stock grants and option awards that are approved in the way the rule requires. Without it, every routine equity award followed by a sale within six months could create liability.

A Rule 10b5-1 trading plan, on the other hand, does not protect an insider from Section 16(b). A plan is a defense against insider trading claims under a different rule. If a planned sale falls within six months of a purchase, it can still be matched. Our guide to 10b5-1 trading plans explains what those plans do cover.

Who enforces it

The SEC does not bring Section 16(b) cases. Under the statute:

• The company can sue to recover the profit.
• If the company does not sue within 60 days after a shareholder asks it to, or does not pursue the case diligently, any shareholder may sue in the company’s name.
• No suit may be brought more than two years after the profit was realized.

The money goes to the company, not the shareholder who sued. In practice, a small group of plaintiffs and law firms reviews Form 4 filings looking for matching trades, and their lawyers are typically paid a fee out of any recovery. Many cases settle without much publicity, and companies often announce settlements in their own filings.

What this means when you read insider data

Section 16(b) shapes insider behavior in ways you can see in the filings. Insiders who buy stock generally avoid selling for at least six months, and vice versa, which is one reason open-market purchases by officers and directors tend to be held for a while. When an insider does buy shortly after a sale, or sells shortly after a buy, it may be a mistake, and you may later see a note in a filing that the insider paid the profit back to the company.

Large investors who cross 10% face the same rule. Some funds that want to trade a stock actively try to stay at or below 10% for that reason. You can see their stakes on our 5% stakes page and their trades, once they are insiders, on our insider trades pages.

Where the rule comes from

• Section 16(b) of the Securities Exchange Act, at 15 U.S.C. 78p, which sets the six-month window, the 60-day shareholder rule and the two-year limit.
• The Supreme Court’s decision in Foremost-McKesson, Inc. v. Provident Securities Co. (1976), on when 10% owners are covered.
• Rule 16a-1, which defines officers and beneficial owners for Section 16.

Examples

CSX, TCI and 3G Capital, 2008. In 2008 the hedge funds The Children’s Investment Fund (TCI) and 3G Capital were in a proxy fight with the railroad CSX. A CSX shareholder, Deborah Donoghue, sued the funds in federal court in New York under Section 16(b) to recover alleged short-swing profits from their trading in CSX securities. In December 2008 CSX announced a settlement in which TCI agreed to pay CSX $10 million and 3G agreed to pay $1 million, subject to court approval. Plaintiff’s counsel planned to ask for up to $550,000 in fees and costs, paid out of the amount going to CSX.

AMC Entertainment and Antara Capital, 2024. AMC shareholders Dennis J. Donoghue and Mark Rubenstein sued Antara Capital, its affiliates and its founder, Himanshu Gulati, under Section 16(b) over purchases and sales of AMC securities. In March 2024 AMC published a settlement notice saying the Antara defendants would pay AMC $3.3 million if the court gave final approval, with AMC named in the suit only for its own benefit. Bloomberg Law later reported that the settlement was approved.

Explain it like I’m 13

Imagine you are on the student council, so you hear about school plans before everyone else. The school makes a rule: if you buy something from the school store and sell it again within six months (or sell first and buy back), any money you make goes to the school, not to you.

It does not matter if you really used a secret or just got lucky. The rule is simple so nobody has to argue about it. That keeps student council members from making quick money off what they might know.

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