Cockroach Theory

Updated on March 27, 2024
Article byPrakhar Gajendrakar
Edited byPrakhar Gajendrakar
Reviewed byDheeraj Vaidya, CFA, FRM

What Is Cockroach Theory?

The Cockroach theory states that if some bad news is revealed about a firm, then more bad news is to be expected. It is a popular theory observed in financial markets. The theory assumes that markets lack transparency. Therefore, speculation of impropriety is likely to unearth several hidden malpractices.

It is called the cockroach theory because cockroaches are not spotted in isolation. When one cockroach is spotted, it suggests a group of cockroaches hiding somewhere. Many decisive investors are wary of this theory. When they sense speculation, they exit their current position.

Key Takeaways

  • Cockroach theory primarily indicates that bad news is common. One piece of evidence uncovers a multitude of infractions in the foreseeable future.
  • When one company gets caught scamming, it triggers a sector-wide investigation where many other companies could get exposed. This chain reaction is the cockroach theory in effect.
  • It is a popular perspective, but many economists consider it highly coincidental. Moreover, this assumption does not always hold true in real-world scenarios—it has been proven false on multiple occasions.
  • The cockroach theory is also used for self-development. Individuals double down on flaws and try to rectify them.

Cockroach Theory Explained

Cockroach theory is a market phenomenon that states that one piece of bad news is usually an indication of more bad news underneath. For example, in 2017, Warren Buffett said about Wells Fargo: “There’s never just one cockroach in the kitchen.”

This phrase gained popularity due to an American newsletter written by Dennis Gartman. Gartman called it a negative indication theory. He highlighted how bad news, by nature, is kept a secret. The cockroach theory predicts when one problem is revealed, there could be more problems that the public is not made aware of. It even resembles the Iceberg Theory—the tip of the iceberg is visible and small, but the actual iceberg is larger and submerged beneath the tip.

There is no smoke without fire. And one cannot always judge the seriousness of fire merely based on smoke. Chances are that situation is grimmer at the epicenter. Traders and investors dislike such speculations. They know that the first piece of negative information indicates imminent catastrophe. Some people use this theory for self-development as well. They identify negatives within themselves and look further to discover more flaws. Once individuals are aware of flaws, they are better equipped to deal with them.

Enron energy company’s accounting practices in 2001 and the New Century Financial Corporation’s bad loan speculation in 2007 are popular examples of cockroach theory. Enron was shut down within one and a half years of the PR nightmare.

Similarly, companies like Adelphia and Tyco were investigated for accounting practices and became victims of the cockroach concept. As a result, both Adelphia and Tyco shut their business.

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Cockroach Theorem Explanation in Video



  • Negative news breeds fear in investors. Like a ripple effect, paranoia spreads across the market. Ultimately, the damage is no longer limited to just one firm or sector.
  • Negative speculations and evidence create a hostile environment. As a result, investors become unusually suspicious about everything.
  • It brings direct or indirect corrections to the market.
  • Many investors consider it as an opportunity to be leveraged.


Now, let us look at some examples to understand cockroach theory.

Example #1

Steven is a capable investor; he invests in various sectors. When news of public banks getting investigated got released, Steven didn’t panic. He knew that his stocks belonged to a private bank, which had nothing to do with public banks. He did not anticipate any changes in his stock’s price.

But soon, news broke out that the government was also going to investigate private banks. There were various speculations about possible errors and contingencies.

By then, it was too late for Steven to react. The news spread quickly, and the market panicked. Due to the market’s overreaction, the entire banking sector was affected. Steven suffered losses.

Example #2

Now Steven had a friend—Robin. Robin also was an investor. But, unlike Steve, Robin was more decisive.

As soon as the news about public banks broke, he sold his stock. He took this action despite having invested in a private bank.

Robin anticipated the effects of cockroach theory and predicted imminent problems. In a way, Robin’s overreaction ended up saving the day. He did not lose any money.


  • It is a popular perspective, but many economists consider it highly coincidental. There is no necessity for this to occur all the time. There is no definite cause behind the prediction. It is merely conjecture.
  • In real-world scenarios, this assumption does not always hold true—it has been proven false on multiple occasions.
  • The theory cannot be applied outside financial markets.
  • It creates unnecessary panic. In the end, it is a bit of a coin toss. Investors are unsure of either outcome.
  • Sometimes an over-cautious approach causes more harm than good. The market corrects itself over time, but the firm that faced problems due to the effects of the cockroach theory does not recover.
  • Market volatility incentivizes owners to reduce transparency.

Frequently Asked Questions (FAQs)

1. Why is it named the cockroach theory?

Warren Buffett first said, “There’s never just one cockroach in the kitchen.” Later, a popular newsletter written by Dennis Gartman ran with it in America. This theory highlights the lack of transparency in business. If one secret gets exposed, more hidden issues could likely surface at any time.

2. What is the cockroach theory in finance?

This theory is related to the stock markets. Investors overreact when a particular firm or sector becomes a victim of bad news. They end up avoiding the whole sector. Investors become paranoid and suspect other firms as well. This theory predicts the behavior of volatile markets. Sometimes, speculations and panic cause considerable damage. The underlying news could be trivial, but the market’s reaction to the news is always substantial.

3. What is the purpose of the cockroach theory?

It is a market theory that predicts the onset of further bad. The first bad news triggers a chain reaction. The theory assumes that, given scrutiny, almost all firms would falter. But this only affects firms that are scrutinized. Neither the media nor law enforcement has the manpower to investigate every firm. This theory is not backed by concrete evidence or causality. In addition to finance, the cockroach theory is a popular self-development technique.

This has been a guide to What is Cockroach Theory and its meaning. Here, we explain how it works, its effects, examples, and criticism. You can learn more about it from the following articles –

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