Stock market index
In finance, a stock index, or stock market index, is an index that measures the performance of a stock market, or of a subset of a stock market. It helps investors compare current stock price levels with past prices to calculate market performance.[1]
Two of the primary criteria of an index are that it is investable and transparent:[2] The methods of its construction are specified. Investors may be able to invest in a stock market index by buying an index fund, which is structured as either a mutual fund or an exchange-traded fund, and "track" an index. The difference between an index fund's performance and the index, if any, is called tracking error.
Indices and passive investment management[edit]
Passive management is an investing strategy involving investing in index funds, which are structured as mutual funds or exchange-traded funds that track market indices.[13] The SPIVA (S&P Indices vs. Active) annual "U.S. Scorecard", which measures the performance of indices versus actively managed mutual funds, finds the vast majority of active management mutual funds underperform their benchmarks, such as the S&P 500 Index, after fees.[14][15]
Unlike a mutual fund, which is priced daily, an exchange-traded fund is priced continuously and is optionable.[16]
Ethical stock market indices[edit]
Several indices are based on ethical investing, and include only companies that meet certain ecological or social criteria, such as the Calvert Social Index, Domini 400 Social Index, FTSE4Good Index, Dow Jones Sustainability Index, STOXX Global ESG Leaders Index, several Standard Ethics Aei indices, and the Wilderhill Clean Energy Index.[17] Other ethical stock market indices may be based on diversity weighting (Fernholz, Garvy, and Hannon 1998). In 2010, the Organization of Islamic Cooperation announced the initiation of a stock index that complies with Sharia's ban on alcohol, tobacco and gambling.[18]
Critics of such initiatives argue that many firms satisfy mechanical "ethical criteria" (e.g. regarding board composition or hiring practices) but fail to perform ethically with respect to shareholders (e.g. Enron). Indeed, the seeming "seal of approval" of an ethical index may put investors more at ease, enabling scams. One response to these criticisms is that trust in the corporate management, index criteria, fund or index manager, and securities regulator, can never be replaced by mechanical means, so "market transparency" and "disclosure" are the only long-term-effective paths to fair markets. From a financial perspective, it is not obvious whether ethical indices or ethical funds will out-perform their more conventional counterparts. Theory might suggest that returns would be lower since the investible universe is artificially reduced and with it portfolio efficiency. (It conflicts with the Capital Asset Pricing Model, see above.) On the other hand, companies with good social performances might be better run, have more committed workers and customers, and be less likely to suffer reputation damage from incidents (oil spillages, industrial tribunals, etc.) and this might result in lower share price volatility,[19] although such features, at least in theory, will have already been factored into the market price of the stock. The empirical evidence on the performance of ethical funds and of ethical firms versus their mainstream comparators is very mixed for both stock[20][21] and debt markets.[22]
