A more thorough explanation:

Definition: A sleeper is a type of security that has the potential to perform well in the market, but is currently undervalued and not attracting much investor attention.

Example 1: Company XYZ is a small startup that has developed a new technology that could revolutionize the industry. However, the company is not well-known and its stock is currently trading at a low price. If the technology takes off and the company becomes successful, the stock could be considered a sleeper.

Example 2: A mutual fund manager identifies a company that has strong financials and a solid business plan, but is currently trading at a discount compared to its peers. The manager believes that the company has the potential to outperform in the future, making it a sleeper investment.

These examples illustrate how a sleeper is a security that is currently undervalued and not receiving much attention from investors, but has the potential to perform well in the future. It is important to note that investing in sleepers can be risky, as there is no guarantee that the security will perform as expected.