Which of these is NOT a typical intervention by government to encourage market efficiency?

Establishing monopolies is not a typical intervention by the government aimed at encouraging market efficiency, but rather the opposite. Market efficiency generally arises in competitive environments where multiple firms can enter and exit the market freely, leading to optimal resource allocation. Governments typically intervene to address inefficiencies, such as those caused by externalities or market power, hence they may tax negative externalities to discourage harmful behaviors, provide subsidies for positive externalities to encourage beneficial activities, and regulate market practices to ensure fair competition.

In contrast, creating or sustaining monopolies tends to reduce consumer choice, lead to higher prices, and generally creates inefficiencies within the market. Therefore, the correct answer highlights an action that works against the principles of promoting efficient market operations, while the other choices represent standard government interventions aimed at correcting market failures or promoting welfare.