Which of the following is NOT considered a liability?

The investment portfolio is not considered a liability because it represents an asset rather than an obligation. An investment portfolio consists of a collection of financial assets that an individual or an organization owns, such as stocks, bonds, and mutual funds, which can generate income or appreciate in value over time. These assets provide economic benefits and can increase an entity's overall net worth.

In contrast, mortgages, accounts payable, and debts are all financial obligations that need to be settled in the future. Mortgages are loans taken out to purchase property, accounts payable are amounts owed to suppliers for goods and services received, and debts are general obligations an entity must pay. Therefore, the investment portfolio stands apart as a beneficial asset rather than a liability.