Overconfidence is confidence in one's judgments beyond what the data, verified experience, and process support. In trading the term concerns how a decision is made, not the simple fact that a trade earned a profit.
How the term is used
Traders speak of overconfidence when conviction leads someone to overestimate the precision of a market view, increase position size without a rule, or skip planned controls. A winning streak can precede these behaviours, but it does not prove the bias: skill, luck, or favourable market conditions may also explain the result.
Technical limit
A large position, a wide stop, or frequent trading is not enough to label an individual trader. Decisions, risk, and process must be compared with the plan set before the results were known. Turnover studies describe samples and average associations; they do not diagnose every account or establish that more trading always causes worse performance. The full overconfidence entry covers the mechanism, signals, and safeguards.
Sources
- CFA Institute, The Behavioral Biases of Individuals — Classifies overconfidence and discusses ways to recognize and mitigate individual biases.
- Brad M. Barber and Terrance Odean, Trading Is Hazardous to Your Wealth — Examines turnover and net outcomes in a large sample of individual investors without diagnosing any single trader.