Stockbrokers often believe that their own expertise will enable them to select stocks that will outperform the market average. This belief best illustrates

Answer: Overconfidence

Explanation:

According to the given question, the given stockbroker belief best illustrating about the overconfidence as stockbroker believes that their expertise in the business administration will enable for selecting the various types of stocks in the market.

The overconfidence is one of the phenomenon in which the person can misjudging their own abilities and the knowledge on the basis of the given circumstances.

That is why the stockbroker of an organization are misjudging their own stock related abilities and expertise. Therefore, Overconfidence is the correct answer.