Which statement best describes externalities and the concept of internalizing them?

• A. Externalities are costs or benefits not reflected in market prices; internalization uses policy tools or corporate actions to reflect true costs/benefits.
• B. Externalities are always captured by market prices.
• C. Internalization eliminates the need for policy interventions.
• D. Internalization only applies to positive externalities.

Answer: (B)

Externalities happen when an activity affects people who aren’t directly involved in the transaction, and those effects aren’t reflected in market prices. Because prices don’t capture these spillovers, the market may overproduce negative externalities (like pollution) or underproduce positive ones (like education or vaccination).

Internalizing externalities means adjusting incentives so the true social costs or benefits are reflected in decisions. This can be done with policy tools such as taxes, subsidies, or regulations that raise or lower the price of the activity, or through corporate actions that account for social impacts in decision making and costs.

The idea that externalities are always captured by market prices isn’t correct, which is why internalization is needed. It also matters that internalization can address both negative and positive externalities and does not by itself eliminate the role of policy—government measures and coordinated actions are often used together to correct the market.