Index fund

An index fund or index tracker is a collective investment scheme (usually a mutual fund or exchange-traded fund) that aims to replicate the movements of an index of a specific financial market, or a set of rules of ownership that are held constant, regardless of market conditions.

Tracking can be achieved by trying to hold all of the securities in the index, in the same proportions as the index. Other methods include statistically sampling the market and holding "representative" securities. Many index funds rely on a computer model with little or no human input in the decision as to which securities are purchased or sold and is therefore a form of passive management.

The lack of active management usually gives the advantage of lower fees and lower taxes in taxable accounts. However, the fees will generally reduce the return to the investor relative to the index. In addition it is usually impossible to precisely mirror the index as the models for sampling and mirroring, by their nature, cannot be 100% accurate. The difference between the index performance and the fund performance is known as the 'tracking error' or informally 'jitter'.

Index funds are available from many investment managers. Some common indices include the Standard & Poor's 500, the Dow Jones Industrial Average the Wilshire 5000, the FTSE 100. Less common indexes come from academics like Eugene Fama and Kenneth French, who created "research indexes" in order to develop asset pricing models, such as their Three Factor Model. The Fama French Three Factor model is used by Dimensional Fund Advisors to design their index funds. Robert Arnott and Professor Jeremy Siegel have also created new competing fundamentally based indexes based on such criteria as dividends, earnings, book value, and sales.

Economic theory
Economist Eugene Fama said, "I take the market efficiency hypothesis to be the simple statement that security prices fully reflect all available information." A precondition for this strong version of the hypothesis is that information and trading costs, the costs of getting prices to reflect information, are always 0 (Grossman and Stiglitz (1980))." A weaker and economically more sensible version of the efficiency hypothesis says that prices reflect information to the point where the marginal benefits of acting on information (the profits to be made) do not exceed marginal costs (Jensen (1978)). Economists cite the efficient market hypothesis (EMH) as the fundamental premise that justifies the creation of the index funds. The hypothesis implies that fund managers and stock analysts are constantly looking for securities that may out-perform the market; and that this competition is so effective that any new information about the fortune of a company will rapidly be incorporated into stock prices. It is postulated therefore that it is very difficult to tell ahead of time which stocks will out-perform the market.[4] By creating an index fund that mirrors the whole market the inefficiencies of stock selection are avoided.

In particular the EMH says that economic profits cannot be wrung from stock picking. This is not to say that a stock picker cannot achieve a superior return, just that the excess return will not exceed the costs of winning it (including salaries, information costs, and trading costs). The conclusion is that most investors would be better off buying a cheap index fund. Note that return refers to the ex-ante expectation; ex-post realisation of payoffs may make some stock-pickers appear successful.


[edit] Indexing methods

[edit] Traditional indexing
Indexing is traditionally known as the practice of owning a representative collection of securities, in the same ratios as the target index. Modification of security holdings happens only when companies periodically enter or leave the target index.


[edit] Synthetic indexing
Synthetic indexing is a modern technique of using a combination of equity index futures contracts and investments in low risk bonds to replicate the performance of a similar overall investment in the equities making up the index. Although maintaining the future position has a slightly higher cost structure than traditional passive sampling, synthetic indexing can result in more favourable tax treatment, particularly for international investors who are subject to U.S. dividend withholding taxes. The bond portion can hold higher yielding instruments, with a trade-off of corresponding higher risk, a technique referred to as enhanced indexing.


[edit] Enhanced indexing
Enhanced indexing is a catch-all term referring to improvements to index fund management that emphasize performance, possibly using active management. Enhanced index funds employ a variety of enhancement techniques, including customized indexes (instead of relying on commercial indexes), trading strategies, exclusion rules, and timing strategies. The cost advantage of indexing could be reduced or eliminated by employing active management.