In finance, the efficient-market hypothesis (EMH), or the joint hypothesis problem, asserts that financial markets are "informationally efficient". In consequence of this, one cannot consistently achieve returns in excess of average market returns on a risk-adjusted basis, given the information available at the time the investment is made.
There are three major versions of the hypothesis: "weak", "semi-strong", and "strong". The weak form of the EMH claims that prices on traded assets (e.g., stocks, bonds, or property) already reflect all past publicly available information. The semi-strong form of the EMH claims both that prices reflect all publicly available information and that prices instantly change to reflect new public information. The strong form of the EMH additionally claims that prices instantly reflect even hidden or "insider" information. Critics have blamed the belief in rational markets for much of the late-2000s financial crisis.[1][2][3] In response, proponents of the hypothesis have stated that market efficiency does not mean having no uncertainty about the future, that market efficiency is a simplification of the world which may not always hold true, and that the market is practically efficient for investment purposes for most individuals.[4]
In political science and economics, the principal–agent problem or agency dilemma concerns the difficulties in motivating one party (the "agent"), to act in the best interests of another (the "principal") rather than in his own interests.
Common examples of this relationship include corporate management (agent) and shareholders (principal), or politicians (agent) and voters (principal).[1] For another example, consider a dental patient (the principal) wondering whether his dentist (the agent) is recommending expensive treatment because it is truly necessary for the patient's dental health, or because it will generate income for the dentist. In fact the problem potentially arises in almost any context where one party is being paid by another to do something, whether in formal employment or a negotiated deal such as paying for household jobs or car repairs.
The problem arises where the two parties have different interests and asymmetric information (the agent having more information), such that the principal cannot directly ensure that the agent is always acting in its (the principal's) best interests,[2] particularly when activities that are useful to the principal are costly to the agent, and where elements of what the agent does are costly for the principal to observe. Moral hazard and conflict of interest may arise. Indeed, the principal may be sufficiently concerned at the possibility of being exploited by the agent that he chooses not to enter into a transaction at all, when that deal would have actually been in both parties' best interests: a suboptimal outcome that lowers welfare overall. The deviation from the principal's interest by the agent is called 'agency costs.'[2]
Various mechanisms may be used to align the interests of the agent with those of the principal. In employment, employers (principal) may use piece rates/commissions, profit sharing, efficiency wages, performance measurement (including financial statements), the agent posting a bond, or the threat of termination of employment.
Public interest theory is an economic theory first developed by Arthur Cecil Pigou[1] that holds that regulation is supplied in response to the demand of the public for the correction of inefficient or inequitable market practices. Regulation is assumed initially to benefit society as a whole rather than particular vested interests.[citation needed] The regulatory body is considered to represent the interest of the society in which it operates rather than the private interests of the regulators.[2]
Regulatory capture is a form of political corruption that occurs when a regulatory agency, created to act in the public interest, instead advances the commercial or special concerns of interest groups that dominate the industry or sector it is charged with regulating. Regulatory capture is a form of government failure; it creates an opening for firms to behave in ways injurious to the public (e.g., producing negative externalities). The agencies are called "captured agencies".