In 1913, at a roulette table in the Monte Carlo Casino, the ball lands on black five times in a row. Sensing opportunity, a couple of players lean in and place small bets on red, thinking the streak had gone on long enough, and that the next spin will probably be red.
The ball continues landing on black. The streak reaches eight, then 10. More people gather around the table, drawn by what they are seeing. Bets on red start to grow. Some players double their stakes after each loss, convinced that the odds are shifting in their favor. It feels like the perfect moment to step in.
Fifteen in a row. Players who were cautious begin pushing larger stacks of chips forward. “The next one has to be red!” Twenty in a row. At that point, people are 100-percent sure the next one will be red, so they double their bets. Others begin placing everything they have.
Black again. By the time the streak finally ended, the ball had landed on black 26 times in a row, and millions of dollars had been lost. What started as a simple streak turned into a chain reaction of larger and larger bets, all driven by the belief that red had to come next.
The Gambler’s Fallacy is when people assume that past outcomes influence future events, even when this is not the case. At the roulette table, players wrongly assumed that the long streak of black results meant that red was more likely to show up in the future, even if each spin of the wheel is independent of all previous spins.
This way of thinking does not stay inside casinos. One of the most common places it appears is in the stock market. You will often hear statements like, “This stock has already dropped so much. It has to go up soon.” But stock prices do not move because they are “due” for a rebound. They move based on what investors expect will happen to the business in the future.
Consider a simple example. Imagine a restaurant near your home that serves bad food and provides poor service. Over time, fewer customers show up, and revenues begin to fall. The decline is gradual at first, then more noticeable as word spreads. If you applied the same thinking as the gamblers in Monte Carlo, you might say, “This restaurant has been doing badly for so long. I’m sure they will be famous soon!” In reality, if they continue to provide bad food and service, they will continue to lose customers and eventually shut down. Poor performance does not automatically create improvement. Only efforts toward improvement create improvement.
Similarly, a public company with declining sales, rising costs, or weak management does not improve simply because its stock price has fallen. A low stock price can inspire action, but inspiration alone is not enough. For things to get better, management has to take corrective action. A low price does not guarantee a reversal, just as repeated losses at the roulette table do not improve your odds on the next spin.
For investors, what matters over the long run is the company’s future earning power. You need to ask whether the business can grow, has a competitive advantage, and can survive difficult periods. These are the factors that drive returns, not the path the stock price took to get where it is today. These questions are hard to answer. They require time and effort, and there is always uncertainty. But they are far more useful than trying to guess whether a stock is “due” for a rebound based on past price movements.
If you do not want to analyze individual businesses in detail, there is a simpler approach. You can spread your investments across many companies and accept that some will go down while others go up. Over time, the overall portfolio will balance out without relying heavily on any single prediction. This reduces the impact of being wrong about any one investment. It also removes the need to make short-term forecasts, which are often unreliable and driven by the same flawed instincts that led gamblers to keep betting on red in the Monte Carlo casino.
The instinct to expect a reversal after losses feels natural, but it can lead to poor decisions. Stocks do not recover just because they have fallen, just as a roulette table does not just “correct” itself because of a long streak. By avoiding this way of thinking and focusing on what actually drives outcomes, you put yourself in a better position to make sound investment decisions, helping you protect your capital and improve your investing.