Mule Haas is a portfolio manager. On average, the expected returns on all securities that Mule is

Question:

Mule Haas is a manager. On average, the expected returns on all securities that Mule is researching are positive. Under what conditions might Mule be willing to purchase a security with a negative expected return?
Portfolio
A portfolio is a grouping of financial assets such as stocks, bonds, commodities, currencies and cash equivalents, as well as their fund counterparts, including mutual, exchange-traded and closed funds. A portfolio can also consist of non-publicly...