Introduction
Insider trading enforcement in the United States has evolved through landmark cases that redefined what constitutes securities fraud, established new legal precedents, and sent shockwaves through Wall Street. Each major prosecution has expanded the reach of regulators and raised the stakes for those who trade on material nonpublic information.
The cases below are ordered roughly by their historical significance and impact on securities law. Together, they tell the story of how insider trading enforcement grew from a relatively obscure corner of securities regulation into one of the most aggressively prosecuted white-collar crimes in the American legal system.
Every fact in this article — every fine, every prison sentence, every date — is drawn from court records, SEC enforcement actions, and Department of Justice press releases. These cases are matters of public record.
Ivan Boesky (1986)
Ivan Boesky was one of the most prominent arbitrageurs on Wall Street in the 1980s, known for making enormous bets on companies involved in mergers and acquisitions. His seemingly uncanny ability to predict takeover targets made him fabulously wealthy and earned him a reputation as a brilliant trader.
In reality, Boesky was paying for inside information. He had a network of investment bankers and corporate insiders who fed him tips about upcoming deals, allowing him to buy shares before public announcements and profit from the resulting price jumps. His scheme unraveled in 1986 when the SEC, acting on tips from other investigations, confronted Boesky with evidence of his illegal trades.
Boesky agreed to pay a $100 million fine — an unprecedented amount at the time — and was sentenced to 3.5 years in federal prison. Critically, Boesky agreed to cooperate with prosecutors, and the information he provided led directly to the investigation and prosecution of Michael Milken, the junk bond king at Drexel Burnham Lambert. Boesky's cooperation helped bring down one of the most powerful figures in 1980s finance.
Michael Milken (1990)
Michael Milken, the head of Drexel Burnham Lambert's high-yield bond department, was the most powerful figure in American finance during the 1980s. He virtually invented the market for high-yield ("junk") bonds and used that market to finance leveraged buyouts that reshaped corporate America.
Milken was indicted in March 1989 on 98 counts of racketeering and securities fraud, charges built in part on cooperation from Ivan Boesky. After lengthy negotiations, Milken pleaded guilty in April 1990 to six felony counts of securities and tax violations (reduced from the original indictment, which had initially included charges related to 10 counts of securities fraud and racketeering). He was originally sentenced to 10 years in prison but served 22 months after his sentence was reduced for good behavior and cooperation.
Milken paid a total of $600 million in fines and settlements — $200 million in fines and $400 million in settlements to injured parties. This remains one of the largest individual penalties in securities enforcement history. Drexel Burnham Lambert itself pleaded guilty to six felony counts and paid $650 million in fines, and the firm filed for bankruptcy in February 1990. Milken received a presidential pardon from President Trump in February 2020.
Raj Rajaratnam / Galleon Group (2011)
The Raj Rajaratnam case was a watershed moment in insider trading enforcement. Rajaratnam, the founder and manager of the Galleon Group hedge fund, was convicted in May 2011 of 14 counts of securities fraud and conspiracy. He was sentenced to 11 years in federal prison — the longest sentence for insider trading at the time of his sentencing — and ordered to forfeit $53.8 million and pay an additional $10 million civil penalty.
What made this case groundbreaking was the government's use of wiretap evidence. For the first time in a major insider trading prosecution, the FBI obtained court authorization to tap Rajaratnam's phone, recording conversations in which he received tips from corporate insiders at companies including Goldman Sachs, Intel, and McKinsey. The wiretaps captured Rajaratnam discussing specific trades based on material nonpublic information, making the evidence nearly impossible to refute.
The Galleon investigation was one of the largest insider trading probes in history, ultimately resulting in the conviction of more than 30 individuals. It demonstrated that the government was willing to use investigative tools previously reserved for organized crime to pursue securities fraud.
Rajat Gupta (2012)
Rajat Gupta's case was among the most stunning falls from grace in corporate history. Gupta had served as the managing director of McKinsey & Company, the elite management consulting firm, from 1994 to 2003. He was also a member of the board of directors of Goldman Sachs and Procter & Gamble.
Prosecutors showed that Gupta tipped Raj Rajaratnam about confidential Goldman Sachs board discussions, including Warren Buffett's $5 billion investment in Goldman during the 2008 financial crisis. Phone records showed that Gupta called Rajaratnam within minutes of learning this information during a Goldman board call, and Galleon purchased Goldman shares before the public announcement.
Gupta was convicted in June 2012 of three counts of securities fraud and one count of conspiracy. He was sentenced to two years in federal prison and fined $5 million. The case underscored that insider trading laws apply equally to the most senior levels of corporate governance — there is no exception for prestige or position.
SAC Capital Advisors / Steven Cohen (2013)
SAC Capital Advisors, the hedge fund founded and run by Steven A. Cohen, agreed to pay a total of $1.8 billion to resolve insider trading charges — the largest insider trading settlement in history. The firm itself pleaded guilty to securities fraud and wire fraud charges in November 2013.
The government's case centered on a pattern of insider trading across the firm. Multiple SAC portfolio managers and analysts were charged with trading on inside information, and prosecutors alleged that the firm's culture prioritized obtaining an "edge" — a term that, in practice, sometimes meant material nonpublic information.
Steven Cohen himself was never criminally charged. However, he was barred from managing outside money by the SEC for two years. SAC Capital ceased operating as a hedge fund and converted to a family office called Point72 Asset Management, which managed only Cohen's personal fortune until the investment management ban expired, after which Point72 began accepting outside capital again.
Martha Stewart / ImClone Systems (2004)
Martha Stewart's case is perhaps the most publicly recognizable insider trading scandal in American history, though it carries an important legal nuance: Stewart was never convicted of insider trading itself. She was convicted of conspiracy, obstruction of justice, and making false statements to federal investigators.
The underlying facts involved Stewart's sale of 3,928 shares of ImClone Systems stock on December 27, 2001, one day before the FDA announced it would reject ImClone's application for its cancer drug Erbitux. Stewart's broker at Merrill Lynch, Peter Bacanovic, had allegedly tipped her that ImClone's CEO, Sam Waksal, was trying to sell his shares — a signal that bad news was imminent.
Stewart sold her ImClone shares for approximately $228,000, avoiding a loss of about $45,673. She was sentenced to five months in federal prison and five months of home confinement. The relatively modest financial stakes made the case notable for what it revealed about the legal system's approach to high-profile defendants: the cover-up was prosecuted more aggressively than the underlying trade.
R. Foster Winans (1985)
R. Foster Winans was a reporter for The Wall Street Journal who co-wrote the paper's influential "Heard on the Street" column. Winans leaked the contents of upcoming columns to a stockbroker named Peter Brant, who traded on the information before the columns were published. The column's recommendations routinely moved stock prices, so advance knowledge of its contents was valuable.
Winans and his co-conspirators made approximately $690,000 in profits from the scheme. Winans was convicted of securities fraud and mail fraud in 1985 and sentenced to 18 months in federal prison.
The case's lasting significance lies in the Supreme Court decision it produced. In Carpenter v. United States (1987), the Court affirmed Winans's conviction on the mail and wire fraud counts, holding that the Journal's confidential information about the timing and content of its columns was the Journal's property, and that Winans's misappropriation of that information constituted fraud. The securities fraud conviction was affirmed by an equally divided 4-4 Court (Justice Powell did not participate). This case was instrumental in developing the misappropriation theory of insider trading, which holds that a person commits fraud when they misappropriate confidential information for securities trading purposes in breach of a duty owed to the source of the information.
Albert Wiggin (1929)
Albert Wiggin was the president of Chase National Bank (a predecessor to JPMorgan Chase) during the 1920s. In the lead-up to and during the stock market crash of 1929, Wiggin sold short approximately 42,000 shares of his own bank's stock through personal corporations he controlled, profiting as Chase's stock price collapsed.
Wiggin made approximately $4 million from his short positions — a fortune in 1929 dollars — while his own bank's shareholders suffered devastating losses. He did this while simultaneously serving as the bank's president, with full knowledge of the institution's financial condition.
When the Senate Banking Committee investigated the crash, Wiggin's short selling was exposed during the Pecora hearings of 1933-1934, led by counsel Ferdinand Pecora. The public outrage over Wiggin's actions and similar abuses by other banking executives was a direct catalyst for the passage of the Securities Exchange Act of 1934, which created the SEC and established the foundational framework for regulating insider trading in the United States. Wiggin was never criminally charged because the laws that would have made his conduct illegal did not yet exist — his case is precisely why those laws were written.
Mathew Martoma / SAC Capital (2014)
Mathew Martoma was a portfolio manager at CR Intrinsic Investors, a unit of SAC Capital Advisors. His case involved one of the most lucrative insider trades ever documented and centered on material nonpublic information about an Alzheimer's drug clinical trial.
Martoma cultivated a relationship with Dr. Sidney Gilman, a professor of neurology at the University of Michigan who served as chairman of the safety monitoring committee for a clinical trial of bapineuzumab, an Alzheimer's drug being jointly developed by Elan Corporation and Wyeth. Gilman provided Martoma with confidential data about the trial's disappointing results before the findings were made public in July 2008.
Armed with this information, SAC Capital liquidated its long positions in Elan and Wyeth and then built a massive short position in both stocks. When the negative trial results were announced publicly, the stocks plummeted, and SAC's trades generated approximately $275 million in profits and avoided losses. Martoma was convicted in February 2014 and sentenced to nine years in federal prison. Dr. Gilman cooperated with the government and was not prosecuted.
Rengan Rajaratnam (2014)
Rengan Rajaratnam, the younger brother of Raj Rajaratnam, was charged in 2013 with conspiracy to commit securities fraud and securities fraud in connection with alleged insider trading at the hedge fund Sedna Capital, which he co-managed. Prosecutors alleged that he traded on tips received from his brother and other sources.
In July 2014, a federal jury acquitted Rengan Rajaratnam on all counts. The acquittal was notable because insider trading prosecutions during this era had an extraordinarily high conviction rate. The government's case against Rengan was widely viewed as weaker than its case against his brother, relying more heavily on circumstantial evidence and less on the kind of direct wiretap evidence that had been so devastating in Raj's trial.
The acquittal served as a reminder that insider trading cases are not automatic convictions for the government, even in an era of aggressive enforcement. It highlighted the importance of direct evidence and the challenges prosecutors face when they cannot demonstrate that a defendant knowingly received and traded on material nonpublic information.
What These Cases Tell Us
Several themes emerge from the history of insider trading enforcement:
The penalties have escalated dramatically. From Wiggin's era, when insider trading was not even illegal, to the $1.8 billion SAC Capital settlement, the consequences of getting caught have grown exponentially. Prison sentences have lengthened, fines have multiplied, and the reputational damage has become career-ending.
Enforcement tools have become more sophisticated. The Rajaratnam case introduced wiretaps to insider trading investigations, fundamentally changing the government's ability to build cases. Before wiretaps, prosecutors relied on trading records, phone logs, and cooperating witnesses. After Rajaratnam, defendants knew that their actual conversations could be played for a jury.
No one is too powerful to prosecute. Rajat Gupta sat on the boards of Goldman Sachs and Procter & Gamble and led McKinsey for nearly a decade. Steven Cohen was one of the most successful hedge fund managers in history. Martha Stewart was a cultural icon. None of these positions provided immunity from prosecution.
Cooperation is the government's most powerful tool. Boesky led to Milken. Rajaratnam's prosecution unraveled a network of more than 30 individuals. The SAC Capital investigation relied on cooperating witnesses at multiple levels of the firm. When someone gets caught, the dominoes tend to fall.
The distinction between legal and illegal insider trading is critical. Every case on this list involves trading on material nonpublic information obtained through deception, breach of duty, or theft. Legal insider trading — where corporate insiders buy and sell stock and report those transactions on SEC Form 4 — is an entirely different activity. It is public, regulated, and, as academic research has shown, genuinely informative for investors.
Why Legal Insider Trading Matters for Investors
The cases above represent the illegal end of the spectrum: people who traded on stolen information and got caught. But the other side of insider trading — the legal, publicly disclosed kind — is where the real opportunity lies for everyday investors.
When a CEO spends $2 million of their own money buying stock in their company and reports that purchase on a Form 4 filing, they are not breaking the law. They are making a public statement of confidence. Academic research, notably the foundational work by Seyhun (1986) and the comprehensive study by Lakonishok and Lee (2001), has consistently shown that these legal insider purchases contain predictive information about future stock returns.
The key is systematic analysis. A single insider purchase could mean anything. But when you aggregate thousands of transactions, score them based on factors like dollar conviction, insider role, cluster patterns, and technical context, clear patterns emerge. The most informative legal insider trades share characteristics that can be identified and tracked programmatically.
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