"ランダムネスに惑わされることは投資家によくあるミスです。"

Investors often trick themselves into thinking that their successes (or failures) are due to skill when, actually, they might just be the result of random chance. This happens a lot in the stock market because it's such an unpredictable place. Prices go up and down for so many reasons, and not all of them are within anyone's control. You might think you're a genius for picking a winning stock, but maybe you just got lucky this time.

Let's dive into some context. This idea became especially popular after Nassim Nicholas Taleb wrote his book "Fooled by Randomness" in 2001. Taleb, a former trader, argued that people, particularly in finance, often mistake luck for talent. They see patterns where there are none and attribute their wins to skill and their losses to bad luck. This mindset can be dangerous because it leads to overconfidence and risky decisions.

Picture this: a new investor, let's call him Jake, starts dabbling in the stock market. He buys shares in a tech company, and suddenly the company announces a major breakthrough. The stock prices soar. Jake is thrilled and pats himself on the back, thinking he’s got a real knack for this. He starts investing more and more, believing he can predict the market. But then, the market takes a downturn, and Jake loses a lot of money. He was fooled into thinking his initial success was due to his investment skills, but really, it was just a stroke of luck.

So, how can you avoid Jake’s mistake? First, always question your assumptions. If you're successful, dig into why that might be. Was it really your doing, or did external factors play a role? Diversify your investments to spread out risk, and don’t throw all your money into one basket just because it worked once. Stay educated about market trends and seek advice from seasoned investors who have been through various market cycles.

Now, imagine a story to really drive this home. Think about Lisa. She’s an artist who decided to invest in the stock market to make some extra cash. Lisa has no background in finance, but she reads a couple of articles and decides to invest in a trendy biotech firm. A few months later, the company announces a new wonder drug, and their stock skyrockets. Lisa is over the moon. She thinks she’s a natural at this and begins investing larger amounts, often in risky, unresearched stocks. She gets a thrill out of seeing her money grow—until it doesn’t. A few bad investments later, she’s lost more than she gained, and she’s frustrated and confused. If only she had remembered that her initial win was just good timing and not necessarily a sign of her investing prowess!

The key takeaway? Don’t let random events dictate your investing strategy. Be humble and cautious. Always analyze your wins and losses with a critical eye. Understand that the market is influenced by countless factors, many of which are out of your control. By keeping a level head and not attributing your success solely to your skills, you’re less likely to fall into the trap of overconfidence and make better, more informed decisions. So, next time you hit a win, enjoy it—but don’t be fooled.