Overconfidence bias is an magnified belief in your competence as a trader. Any trader who finds themselves thinking that they know the business inside-out and that they have nothing more to learn and that profits are theirs for the taking, may well suffer from an overconfidence bias. 

Dangers of Overconfidence 
Overconfident traders tend to get themselves into trouble by trading too frequently or by placing tremendously large trades with the plan of making a killing. It’s not inevitable, but an overconfident investor invites misfortune. 

Are You Overconfident? 
If you want to identify whether you have a tendency to be overconfident, ask yourself, “Have I ever delayed or reversed a decision because I couldn’t accept that I was wrong?” Likewise, you could ask yourself, “Have I ever placed more on a trade than what I know is really sensible?” 

Overcoming Overconfidence 
One way to overcome an overconfidence bias is to stick to a strict set of risk management rules. These rules should limit the number of markets you invest in, the number of Contracts for difference you trade at one time, how much you are willing to risk on any one trade and how much of your account are you willing to lose before you take a break from trading and re-evaluate your trading strategy.