What Is Insider Trading and When Is It Legal?

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Insider trading is buying or selling a security while in possession of material, nonpublic information about it, in breach of a duty of trust or confidence owed to the source of that information. “Material” means a reasonable investor would consider the information important. “Nonpublic” means it has not been released to the market. Trading on that information is illegal in the United States, and so is passing it to someone who trades.

The term also has a broader, lawful sense. Executives, directors and large shareholders trade their own company’s stock every day, and those trades are legal when the insider holds no undisclosed material information and follows the reporting and trading rules of the Securities and Exchange Commission (SEC). Lawyers usually call that activity “insider transactions.” Trading by insiders can be legal, while trading on inside information in breach of a duty is not.

What counts as insider trading

No federal statute contains a single, complete definition of insider trading. The prohibition rests mainly on Section 10(b) of the Securities Exchange Act of 1934, the law that created the SEC, and on Rule 10b-5, which the SEC adopted under it in 1942. Together they forbid fraud and deception in connection with buying or selling securities. Courts have spent decades working out when trading on undisclosed information counts as that kind of fraud. The SEC’s own summary of the result is trading a security “in breach of a fiduciary duty or other relationship of trust and confidence, based on material, nonpublic information about the security.” Each part of that sentence does work, and a case fails if any part is missing.

Who counts as an insider

Securities law uses “insider” in two different senses. The narrow one comes from Section 16 of the Exchange Act and covers statutory insiders: officers, directors, and beneficial owners of more than 10% of a registered class of the company’s equity securities. These people have special reporting obligations and are subject to the short-swing profit rule described below.

The insider trading prohibition reaches a much wider group:

• Corporate insiders: officers, directors and employees at any level. A junior analyst who sees next quarter’s numbers before release owes the same duty not to trade on them as the chief executive does.
• Temporary or constructive insiders: people who receive confidential information because they work for or with the company, such as outside lawyers, auditors, investment bankers and consultants. Their duty comes from the relationship, not from employment.
• Misappropriators: outsiders who take confidential information from a source to whom they owe a duty and trade on it. A lawyer at a firm advising an acquirer who buys shares of the target falls into this category even though he owes nothing to the target’s shareholders.
• Tippees: anyone who receives material nonpublic information from an insider or misappropriator and trades while knowing, or having reason to know, that it was disclosed in breach of a duty. Tippees can pass information on to further tippees, and liability can follow the chain.

What makes information material

Information is material if there is a substantial likelihood that a reasonable investor would consider it important in deciding whether to buy, sell or hold the security, or if it would significantly alter the total mix of available information. There is no fixed percentage or dollar threshold. The question is judged by context, including how likely an event is and how large its effect would be if it happened.

Topics that have repeatedly appeared in SEC enforcement actions include:

• Pending mergers, acquisitions and tender offers
• Earnings results or guidance before release, including figures like earnings per share that differ from what the market expects
• Regulatory decisions, such as FDA approvals or rejections of a drug
• Major contracts won or lost, significant litigation, and changes in senior management
• Cybersecurity incidents, dividend changes and planned securities offerings

Information about a contingent event can be material before the event is certain. Merger talks can be material while the deal is still being negotiated, because a reasonable investor would weigh both the probability of a deal and its likely price.

When information is nonpublic

Information is nonpublic until it has been disseminated in a way that makes it available to investors generally, typically through a press release, an SEC filing, or a broadly accessible conference call, and the market has had a chance to absorb it. Information shared within a company, a deal team, or a small circle of advisers remains nonpublic even if dozens of people know it.

Two consequences follow. First, an insider who trades seconds after a press release crosses the wire may still be trading before the market has absorbed it, which is why many companies keep their trading windows closed for a period after an announcement. Second, information that an analyst assembles from public sources and legitimate research is not inside information, even if the analyst’s conclusion is valuable and not widely held.

The duty requirement

The duty element is what separates illegal insider trading from simply knowing more than other traders. The United States does not have a general “parity of information” rule. In Chiarella v. United States (1980), the Supreme Court overturned the conviction of a financial printer employee who deduced takeover targets from documents he was printing, holding that silence is fraudulent only when there is a duty to speak. Because he owed no duty to the shareholders he traded with, the classical theory did not reach him.

The gap that decision exposed was later closed by the misappropriation theory, which the Supreme Court endorsed in United States v. O’Hagan (1997). There a lawyer whose firm represented a company planning a tender offer bought shares and options in the target. He owed no duty to the target’s shareholders, but he deceived his firm and its client by using their confidential information for himself, and that breach supported liability.

For tips, Dirks v. SEC (1983) held that a tippee inherits a duty only when the insider breached a duty by disclosing the information for a personal benefit, and the tippee knew or should have known of the breach. In Salman v. United States (2016), the Court confirmed that giving confidential information as a gift to a trading relative or friend can satisfy the personal-benefit test.

In 2000 the SEC adopted Rule 10b5-2, which lists relationships that create a duty of trust or confidence for misappropriation purposes: an agreement to keep information confidential, a history or practice of sharing confidences, and receipt of information from a spouse, parent, child or sibling, unless the recipient can show there was no reasonable expectation of confidentiality.

Why insider trading is illegal

The legal answer is that trading on information obtained through a breach of duty is a form of securities fraud. The insider who stays silent while trading deceives the shareholders on the other side, and the misappropriator deceives the source who entrusted the information.

The policy answer is market confidence. If investors believe that people with privileged access routinely trade against them, they demand a higher return, trade less or stay out of the market, which raises companies’ cost of capital and reduces liquidity for everyone. There is also an incentive problem: an executive who can profit from bad news before it is released has a reason to delay disclosure or manage information for personal gain.

The rule does not require that the counterparty lose money because of the insider specifically. A seller who sold to an insider would likely have sold to someone else at the same price. The harm the law targets is the abuse of a confidential position and the damage to the fairness of the market as a whole.

How the modern rules developed

For decades after 1934, federal law relied mostly on disclosure and the short-swing rule. In In re Cady, Roberts & Co. (1961), the SEC disciplined a broker who sold shares after learning, from a partner who sat on the company’s board, that a dividend cut was coming. The decision set out the “disclose or abstain” principle: a person with material nonpublic information obtained through a special relationship must either disclose it before trading or refrain from trading. Since the information usually cannot be disclosed without breaching confidentiality, the practical result is abstain.

SEC v. Texas Gulf Sulphur Co. (1968) applied the principle broadly. Company employees and their associates bought stock and options after a major mineral discovery in Canada and before the company announced it. The Second Circuit took an expansive view, suggesting that anyone in possession of material inside information must disclose or abstain. The Supreme Court later narrowed that view in Chiarella and Dirks by insisting on a duty, but Texas Gulf Sulphur remains a landmark on materiality and on when information becomes public.

Congress added stronger remedies in the 1980s, authorizing civil penalties of up to three times the profit gained or loss avoided and, through the Insider Trading and Securities Fraud Enforcement Act of 1988, extending liability to people who control violators and fail to take appropriate steps to prevent the violations. The Sarbanes-Oxley Act of 2002 raised criminal penalties and shortened the Form 4 filing deadline. The Dodd-Frank Act of 2010 created the SEC whistleblower program. The Stop Trading on Congressional Knowledge (STOCK) Act of 2012 confirmed that members of Congress and their staff owe a duty not to trade on nonpublic information they learn through their positions.

When trading by insiders is legal

Trading by insiders is legal when the trader has no material nonpublic information at the time of the trade (or qualifies for an affirmative defense) and complies with reporting rules, the short-swing profit rule and company policy.

Trading after information is public

Once the company has fully disclosed the relevant information and the market has had time to absorb it, an insider may trade, provided the insider does not hold some other material nonpublic information. Many public companies set trading windows that open a set period after an earnings release and close before the end of the next quarter, and they require officers and directors to pre-clear trades with the general counsel. These are company policies rather than SEC rules, and they vary from company to company. Since the 2022 amendments described below, companies must disclose whether they have adopted insider trading policies and procedures, and explain why if they have not.

Rule 10b5-1 trading plans

Insiders often hold large amounts of company stock and need to sell for diversification, taxes or personal reasons, but they almost always know something about the company that the public does not. Rule 10b5-1, adopted in 2000, addresses that problem. It first clarifies that trading “on the basis of” material nonpublic information means trading while aware of it. It then provides an affirmative defense for trades made under a binding contract, instruction or written plan adopted at a time when the person was not aware of material nonpublic information.

To qualify, the plan must do one of three things:

1. Specify the amount, price and date of the trades;
2. Provide a written formula, algorithm or computer program for determining amounts, prices and dates; or
3. Prevent the trader from exercising any later influence over how, when or whether trades occur, with any person who does exercise that influence (such as a broker) not being aware of material nonpublic information when doing so.

The defense also requires that the plan be entered into in good faith and not as part of a scheme to evade the rules.

The 2022 amendments to Rule 10b5-1

Critics argued for years that the original rule was too easy to abuse. Plans could be modified or cancelled without public disclosure, and trading could begin almost immediately after adoption. An executive could set up a plan, learn of coming bad news, and then adjust or terminate it ahead of the announcement while still pointing to the plan as a defense.

In December 2022 the SEC adopted amendments that tightened the conditions for the defense:

• Cooling-off periods. Directors and officers must wait until the later of 90 days after adopting or modifying a plan or two business days after the company discloses its financial results for the quarter in which the plan was adopted, with the wait capped at 120 days. Other persons, apart from the issuer, face a 30-day cooling-off period.
• No overlapping plans. Persons other than issuers generally may not rely on the defense if they maintain more than one plan for open-market trades in the same class of securities at the same time, subject to limited exceptions.
• Single-trade plans. Reliance on the defense for a plan designed to execute a single trade is limited to one such plan in any 12-month period.
• Certifications. Directors and officers adopting or modifying a plan must certify in the plan that they are not aware of material nonpublic information and are adopting it in good faith.
• Good-faith operation. The trader must act in good faith with respect to the plan throughout its life, not only at adoption.

The amendments added disclosure requirements as well. Companies must report quarterly whether directors and officers adopted or terminated plans, and Forms 4 and 5 now include a checkbox indicating whether a reported transaction was made under a plan intended to satisfy Rule 10b5-1(c).

Section 16 reporting

Statutory insiders must report their holdings and trades to the SEC on three forms:

Filing these forms is a legal obligation, not a safe harbor. A chief executive who sells shares while aware of an undisclosed earnings miss and then files a timely Form 4 has still engaged in illegal insider trading. The form simply creates a public record of the trade.

Short-swing profits under Section 16(b)

The short-swing rule operates independently of the insider trading prohibition. If a statutory insider buys and sells (or sells and buys) the company’s equity securities within any six-month period, the company, or a shareholder suing on its behalf, can recover the profit. It is a strict liability rule: no inside information or intent is needed. Courts match transactions to produce the largest recoverable profit, so a series of trades can create liability even when the insider lost money overall. Insider trading liability, by contrast, requires material nonpublic information and a breach of duty but has no fixed time window, so a person can violate one rule without violating the other.

Forms of illegal insider trading

Classical insider trading

A corporate insider trades the company’s own securities while aware of material nonpublic information. A chief financial officer who sells shares after learning that the company will report a large unexpected loss, before the loss is announced, fits this pattern. The duty is owed to the company’s shareholders.

Tipping

The insider does not trade but passes the information, in breach of duty and for a personal benefit, to someone who does. The tipper can be charged without making a single trade, and the tippee is liable if they knew or should have known the information came from a breach.

Misappropriation

An outsider trades on confidential information taken from a source to whom they owe a duty, such as an employer, a client or a family member. The theory covers lawyers, bankers, printers, journalists and relatives.

Front-running

Front-running occurs when a broker or other market participant trades for their own account ahead of a pending client order. A broker who buys before executing a large client buy order and sells after it lifts the price profits at the client’s expense. Like insider trading it exploits confidential information, but the information concerns order flow rather than the company, and it is generally pursued as a breach of the broker’s duty to customers and a violation of exchange and FINRA rules.

Shadow trading

Shadow trading means using material nonpublic information about one company to trade securities of a different, economically linked company, such as a competitor or close peer. News about one firm often moves others in its industry, which is what makes the practice possible.

The SEC tested the theory in SEC v. Panuwat. Matthew Panuwat, then an executive at the biopharmaceutical company Medivation, learned that his company was about to be acquired by Pfizer. Within minutes he bought short-term out-of-the-money call options in Incyte, another mid-cap oncology company that he expected would rise in value once the deal became public. In 2024 a jury found him liable. The company’s insider trading policy barred employees from using its confidential information to trade in the securities of other public companies, which helped establish the duty.

The SEC’s enforcement director said there was nothing novel about the case, while commentators who disagreed saw a meaningful expansion of liability. Either way, a confidentiality duty can extend to trades in companies other than the one the information is about, depending on the facts and the policies the trader agreed to.

Hypothetical example: how gains and penalties are measured

This hypothetical example shows the mechanics. The names, prices and amounts are invented.

Dana works in corporate development at Acme Industries. On Monday she learns that Acme will announce on Friday an agreement to acquire Beacon Tools for $40 per share in cash. Beacon’s stock trades at $28. Dana tells her brother, Sam, who buys 5,000 shares of Beacon at $28 on Tuesday.

On Friday the deal is announced and Beacon jumps to $39. Sam sells at $39.

Profit gained: (39 − 28) × 5,000 = $55,000, before commissions. This calculation assumes the full move from purchase to sale is attributable to the deal news. In real cases, courts and the SEC typically measure the gain using the price shortly after the information becomes public, so the figure can differ from Sam’s actual sale proceeds if he held longer.

What this means in an enforcement action:

• Disgorgement: the SEC can ask the court to order Sam to give up the $55,000, usually with prejudgment interest.
• Civil penalty: up to three times the profit, here up to $165,000 on top of disgorgement.
• Tipper exposure: Dana never traded, but tippers can be ordered to pay a civil penalty measured by the tippee’s profit, so she could also face up to three times the $55,000. Acme, as her employer, could face controlling-person scrutiny if its controls were inadequate.
• Criminal exposure: both could face prison time and criminal fines, with sentencing guidelines heavily influenced by the size of the gain.

The same arithmetic applies to losses avoided. If Dana had learned of a coming earnings collapse and Sam had sold at $28 shares that fell to $18 after the announcement, the “loss avoided” of $10 per share would be the measure for disgorgement and penalties.

How insider trading is detected and enforced

Insider trading is difficult to prove. Direct evidence such as a recorded conversation is uncommon, so cases often rest on circumstantial evidence: the timing and size of trades, phone records, relationships, and whether the trader had any prior history in the stock. Detection and enforcement involve several bodies.

Market surveillance

The SEC and FINRA use data analytics to look for unusual trading ahead of earnings releases, mergers and regulatory decisions, and FINRA and the exchanges send referrals from their own surveillance to the SEC. Investigators then request trading records from brokers and link accounts through shared addresses, phone numbers, schools, employers and social connections, which is how many tipping chains are traced.

Options activity

Options give leverage, so a trader with inside information can turn a small outlay into a large gain. That same feature makes options trades stand out. Purchases of short-dated, out-of-the-money calls shortly before a takeover announcement are a recognized red flag, and a number of SEC cases have involved exactly that pattern.

Tips, whistleblowers and cooperation

The whistleblower program created under the Dodd-Frank Act pays awards, which have reached many millions of dollars, to individuals whose original information leads to a successful enforcement action with sanctions above a threshold. Tips also come from investors, company compliance departments and, as the cases below show, family members. Cooperating defendants who testify against others are central to many large prosecutions, particularly those involving hedge funds and expert networks.

Coordination

The SEC handles civil enforcement. It can investigate, subpoena records and bring lawsuits or administrative proceedings, but it cannot imprison anyone. The Department of Justice brings criminal cases through U.S. attorneys’ offices, often with the FBI, and the two frequently file parallel actions against the same defendant on the same day. The SEC also works with foreign regulators when trades run through overseas accounts. A typical case moves from a surveillance alert or tip, to an investigation, to charges, and then to a settlement, plea or trial.

Penalties for insider trading

Consequences can be civil, criminal and professional, and they can be imposed together.

Civil remedies (SEC):

• Disgorgement of profits gained or losses avoided, usually with prejudgment interest.
• Civil money penalties of up to three times the profit gained or loss avoided.
• Controlling-person penalties against employers and supervisors who knew or recklessly disregarded the likelihood of violations and failed to take appropriate steps to prevent them.
• Injunctions barring future violations.
• Officer and director bars, which prohibit a person from serving as an officer or director of a public company, permanently or for a set period, when the conduct shows unfitness to serve.
• Industry bars for registered professionals such as brokers and investment advisers.

Criminal penalties (DOJ) for willful violations of the Exchange Act:

• Imprisonment of up to 20 years per violation.
• Fines of up to $5 million for individuals and up to $25 million for entities.
• Forfeiture of proceeds.

Actual sentences depend on the federal sentencing guidelines and the facts, with the amount of gain and the defendant’s criminal history weighing heavily. People charged also typically lose their jobs, professional licenses and reputations, and some face private lawsuits from investors who traded at the same time.

Notable insider trading cases

Martha Stewart and ImClone (charged 2003)

In late 2001, ImClone Systems was waiting on an FDA decision about its cancer drug Erbitux. Peter Bacanovic, a Merrill Lynch broker, learned that ImClone’s chief executive, Samuel Waksal, and his daughter were trying to sell all of their ImClone shares held at Merrill Lynch. Stewart sold close to 4,000 shares after Bacanovic’s assistant passed her that information. When the FDA refused to file ImClone’s application shortly afterward, the stock fell 16% in one day. Stewart’s sale avoided a loss of $45,673.

The SEC charged Stewart with securities fraud for illegal insider trading, and a separate federal indictment brought criminal charges. At her 2004 trial she was convicted not of insider trading but of conspiracy, obstruction of an agency proceeding and false statements to investigators, and she served five months in federal prison. The case is cited for two points: the inside information concerned another person’s trading rather than the drug, and the cover-up produced the prison sentence.

Rajat Gupta and Goldman Sachs (convicted 2012)

Rajat Gupta, a former managing director of McKinsey & Company, sat on the board of Goldman Sachs. In September 2008, during the financial crisis, Goldman’s board approved a $5 billion investment by Berkshire Hathaway. About 16 seconds after Gupta disconnected from the board call, a call was placed to Raj Rajaratnam, founder of the Galleon Group hedge fund, with Gupta connected. Galleon funds bought Goldman shares before the investment was announced.

Prosecutors said Gupta’s tips produced illicit profits and avoided losses of more than $23 million for Rajaratnam. Gupta was convicted of conspiracy and securities fraud and sentenced in 2012 to two years in prison, one year of supervised release and a $5 million fine. He never traded the shares himself, and his conviction, upheld on appeal, is a leading example of tipper liability.

Amazon earnings tip (charged 2017)

Brett Kennedy, a financial analyst at Amazon, gave a fellow University of Washington alumnus, Maziar Rezakhani, information about Amazon’s first-quarter 2015 earnings before their release. Authorities said Rezakhani paid Kennedy $10,000 for the information, and the SEC said he made about $116,000 trading Amazon shares on the tip. A mid-level employee with access to pre-release results is an insider, and a cash payment is a clear personal benefit.

Netflix subscriber numbers (judgments 2022)

Former Netflix engineers tipped friends and relatives about the company’s subscriber growth figures before quarterly releases. In 2022 the SEC obtained final judgments in the case. The defendants who profited were ordered to forfeit amounts totaling about $3.2 million and received prison terms of 13 to 24 months, while another defendant received probation. Subscriber growth was a figure investors watched closely, which made it plainly material.

TravelCenters of America and the overheard spouse (sentenced 2024)

Tyler Loudon’s wife was a mergers and acquisitions manager at BP, working remotely on the company’s planned acquisition of TravelCenters of America. In late 2022, including during a stay in Rome, she worked on and discussed the deal within his hearing. Over roughly seven weeks Loudon bought 46,450 shares of TravelCenters and made about $1.7 million when the acquisition was announced and the stock jumped.

Loudon was not an employee of either company. His liability came from the relationship of trust and confidence with his spouse. In spring 2023 his wife learned of the trades and reported them to BP, which alerted authorities. Loudon was sentenced to two years in federal prison, forfeited the proceeds and was ordered to pay disgorgement and prejudgment interest. The case illustrates the Rule 10b5-2 spousal duty and how often detection starts with someone close to the trader rather than with surveillance software.

Where to find insider trading data

Lawful trades by statutory insiders are public. Forms 3, 4 and 5 are filed electronically and can be searched on the SEC’s EDGAR system by company name or ticker symbol. The SEC also publishes downloadable insider transaction datasets extracted from these filings. Many financial websites and stock screeners repackage the same filings into lists of recent insider buys and sells.

Reading the data well requires knowing what the codes and context mean:

• Purchase versus sale. Open-market purchases with personal money are often read as confidence. Sales happen for many reasons, including diversification, taxes, home purchases and estate planning, so a single sale says little.
• Option exercises and awards. Grants, vesting events and option exercises, sometimes with shares sold to cover the exercise price or tax, are compensation mechanics rather than market bets.
• The 10b5-1 checkbox. A plan trade reflects a decision made at adoption, not a reaction to current conditions.
• Clusters. Several insiders buying in the same short period carries different information than one director’s trade.
• Size relative to holdings. A sale of 2% of an executive’s position differs from a sale of 80%.

Insider data works alongside valuation measures such as the P/E ratio and the company’s own disclosures, not as a substitute for them. Reported trades reveal nothing about illegal trading, which happens in accounts not reported as insider transactions.

Distinctions that are commonly confused

Insider trading vs. insider transactions

Insider transactions are all trades by officers, directors, employees and large shareholders in their own company’s securities, and most filed with the SEC are lawful. Insider trading in the legal sense is the subset made while aware of material nonpublic information in breach of a duty. Employees can and do trade company stock legally, subject to company trading windows and the law.

Insider trading vs. superior research

An investor who builds an informational edge through public filings, industry data, channel checks and analysis is not trading on inside information, even if the conclusion turns out to be valuable. Analysts sometimes describe this as assembling a “mosaic” from public and non-material pieces. The line is crossed when a piece of the mosaic is itself material, nonpublic information obtained in breach of a duty, such as a tip from a company employee about unreleased sales figures.

Insider trading vs. market manipulation

Insider trading exploits information the market does not have. Market manipulation creates false or misleading impressions about price or volume, as in pump-and-dump schemes, spoofing or wash trades. Both violate federal securities laws, but they rest on different theories, and a manipulator need not have any inside information at all.

Insider trading vs. overhearing a stranger

Because liability depends on a duty, someone who overhears two strangers discussing a merger in a restaurant and trades on it is not automatically liable in the United States. The result changes if the listener has a relationship of trust with the speaker (as in the Loudon case), took the information improperly, or knows it was disclosed in breach of a duty for a personal benefit. The line is narrow enough that trading on such information is a serious legal risk.

U.S. law vs. other jurisdictions

The duty-based approach is specific to U.S. federal law. The European Union’s Market Abuse Regulation and the United Kingdom’s regime prohibit dealing on inside information without the same reliance on a fiduciary duty, and India’s regulator, SEBI, enforces its own Prohibition of Insider Trading Regulations. Anyone trading on a non-U.S. market is subject to that market’s rules, which may reach conduct U.S. law would not.

Limitations and gray areas

• No statutory definition. Because the prohibition comes largely from case law interpreting a general antifraud rule, the boundaries move with court decisions. The personal-benefit test, the reach of the misappropriation theory, and shadow trading have all been litigated.
• Materiality is judged after the fact. A trader decides what is important before the market reacts, while regulators and juries evaluate it knowing the price moved.
• Plans can still be gamed. The 2022 amendments reduced the flexibility of 10b5-1 plans, but a person who adopts a plan while aware of material information, or operates it in bad faith, loses the defense.
• Intent and knowledge. Civil liability requires scienter, meaning intent to deceive or recklessness, and criminal liability requires willfulness. A tippee who genuinely had no reason to suspect the information was confidential or improperly disclosed may have a defense, but the standard includes what the person “should have known.” Courts look at the relationship with the source, how specific the information was and whether the trader had another reason to trade. Claims of innocent ignorance are weak when the source is a relative or friend at the company, or when the trades are unusual for the account.
• Detection is uneven. Large, well-timed trades in liquid stocks around major announcements are easier to spot than small trades spread across accounts, or shadow trades in related companies.

FAQs

The Bottom Line

Executives, employees, outside advisers and their relatives face the most direct risk, since a duty can come from a job, a client relationship or a family tie. Anyone with material nonpublic information should abstain from trading unless a qualifying Rule 10b5-1 plan was adopted beforehand. Investors reading public insider filings should weigh context, such as plan trades, clusters and position size, before treating a sale or purchase as a signal.