The American upper class describes the sociological concept pertaining to the "top layer" of society in the United States. This social class is most commonly described as consisting of those with great wealth and power and may also be referred to as the Capitalist Class or simply as The Rich. Persons of this class commonly have immense influence in the nation's political and economic institutions as well as public opinion.

Many politicians, heirs to fortunes, top business executives, CEOs, successful venture capitalists and celebrities are considered members of this class. Some prominent and high-rung professionals may also be included if they attain great influence and wealth. The main distinguishing feature of this class, which is estimated to constitute roughly 1% of the population, is the source of income. While the vast majority of persons and households derive their income from salaries, those in the upper class derive their income from investments and capital gains. Estimates for the size of this group commonly vary from 1% to 2%, while some surveys have indicated that as many as 6% of Americans identify as "upper class." Sociologist Leonard Beeghley sees wealth as the only significant distinguishing feature of this class and, therefore, refers to this group simply as "the rich."

" "The members of the tiny capitalist class at the top of the hierarchy have an influence on economy and society far beyond their numbers. They make investment decisions that open or close employment opportunities for millions of others. They contribute money to political parties, and they often own media enterprises that allow them influence over the thinking of other classes... The capitalist class strives to perpetuate itself: Assets, lifestyles, values and social networks... are all passed from one generation to the next." -Dennis Gilbert, The American Class Structure, 1998 "

Sociologists such as W. Lloyd Warner, William Thompson and Joseph Hickey recognize prestige differences between members of the upper class. Established families, prominent professionals and politicians may be deemed to have more prestige than some entertainment celebrities who in turn may have more prestige than the members of local elites. Yet, contemporary sociologists argue that all members of the upper class share such great wealth, influence and assets as their main source of income as to be recognized as members of the same social class. As great financial fortune is the main distinguishing feature of this class, sociologist Leonard Beeghley at the University of Florida identifies all "rich" households, those with incomes in the top 1% or so, as upper class.

Functional theorists in sociology and economics assert that the existence of social classes is necessary in order to distribute persons so that only the most qualified are able to acquire positions of power, and so that all persons fulfill their occupational duties to the greatest extent of their ability. Notably, this view does not address wealth, which plays an important role in allocating status and power.

In order to make sure that important and complex tasks are handled by qualified and motivated personnel, society offers incentives such as income and prestige. The more scarce qualified applicants are and the more essential the given task is, the larger the incentive will be. Income and prestige which are often used to tell a person's social class, are merely the incentives given to that person for meeting all qualifications to complete an important task that is of high standing in society due to its functional value.

"It should be stressed... that a position does not bring power and prestige because it draws a high income. Rather, it draws a high income because it is functionally important and the available personnel is for one reason or another scarce. It is therefore superficial and erroneous to regard high income as the cause of a man's power and prestige, just as it is erroneous to think that a man's fever is the cause of his disease... The economic source of power and prestige is not income primarily, but the ownership of capital goods (including patents, good will, and professional reputation). Such ownership should be distinguished from the possession of consumers' goods, which is an index rather than a cause of social standing." -Kingsley Davis and Wilbert E. Moore, Principles of Stratification. "

As mentioned above, income is one of the most prominent features of social class, but not necessarily one of its causes. In other words, income does not determine the status of an individual or household but rather reflects upon that status. Income and prestige are the incentives in order to fill all positions with the most qualified and motivated personnel possible.