Overconfidence bias

Overconfidence is the tendency to overestimate your own knowledge, skill and the accuracy of your predictions. Surveys repeatedly find that the large majority of people rate themselves above-average drivers — a statistical impossibility. Traders are no different, and the market punishes it directly.

The market example

A trader has three winning trades in a row. Confidence surges. On the fourth idea, instead of risking the usual 1% of the account, they "know" this one is a sure thing and risk 8%. The trade goes against them and erases the prior three wins plus more. The skill did not change between trade three and trade four — only the self-assessment did.

Overconfidence shows up as oversized positions, overtrading, ignoring stop losses ("I'll just watch it"), and dismissing information that doesn't fit your view.

Why it is especially dangerous after success

A winning streak feels like proof of skill, but in any strategy with a positive edge, streaks are simply normal variance. Attributing them to genius leads directly to the bet that gives it all back. Notably, the more a trader knows, the more prone they often are — a little expertise breeds a lot of false certainty.

How to counter it

• Keep position size constant regardless of how confident you feel. Confidence is not an input to your risk formula.
• Track your actual win rate in a journal. Real numbers puncture inflated self-assessment.
• Write down your prediction and the reasons before a trade. Review later how often you were right and right for the reason you thought.
• Treat winning streaks as a yellow flag, not a green light, for sizing up.