What is an Index Fund and how does it work?

What is an Index Fund

An index fund is a type of mutual fund with a portfolio structured to match or track the components of a market index.

When you invest in an index fund, you gain access to a wide variety of assets that operate in the same market. Rather than just investing in one asset, index funds provide broad market risk, low operating costs, and low portfolio turnover rates.

These funds adhere to certain rules or standards that remain the same no matter how the markets work.

Although an index is made up of stocks or bonds that satisfy a number of required characteristics, the decision-making process is effectively passed on to those responsible for developing the index. This can save investors a lot of money because there is no need to pay the mutual fund manager to make such decisions.

Regardless, the index fund still has a portfolio manager who works to get results as close to the index as possible. The best way to do this is to buy and sell assets when they join or leave the index list. 

The hardest part to do this is to minimize taxable return on capital, that is, the gains made from buying and selling a position in the market.

An index is a list of stocks or bonds based on a set of rules. For example, Standard Poor’s 500 (SP 500) is a list of the top 500 stocks traded on the New York Stock Exchange by market capitalization. This form of passive investing provides access to a wide range of assets in the market. 

How index funds work

A market index measures the performance of a group of securities that represent a particular economic market or sector. But you cannot directly invest in a market index. If you want to achieve a return that is approximately equal to the return of an index, you can use an index fund. When you buy shares of an index fund through a discount broker or investment firm, you are investing indirectly in the securities they are investing in directly.

These funds buy all or only a representative sample of the companies included in the index in order to generate similar returns. For example, the well-known Dow Jones Industrial Average (DJIA) measures the performance of 30 large American companies, which cover all business sectors except transportation and utilities. State Street Global Advisors’ SPDR Dow Jones Industrial Average ETF Trust supports all 30 of these companies in its holdings to mimic the DJIA performance. In contrast, the Dow Jones General US Stock Market Index represents all US-listed stocks and supports over 3,700 companies. The Schwab Total Stock Market Index Fund aims to replicate the results of this index by maintaining participation in a representative sample of the companies included in the index.

Because fund managers do not actively select securities to include in their portfolios, but instead only buy those that are in the index they follow, index funds are considered passively managed investments.

Many stock indices (but not DJIAs) use market caps to weigh securities. This means that those companies whose stocks have a higher market cap or total value are more strongly represented in the index. A basic trick for index fund managers is to match the weights of the stocks in the fund with the weights in the index.

Pros and cons of index funds

These tools have more advantages than disadvantages:

What we like:

  • Index Mapping Performance
  • Low costs
  • Tax efficiency
  • Wide diversification

What we don’t like:

  • No exact match for index returns
  • Market capitalization could cause a sharp drop

More about the pros

There are four main reasons why investors buy index funds for their investment portfolio.

Index Matching Metrics: Actively managed funds strive to exceed targets. But year after year, they fail. In 2019, only about 40% of these funds – of all investment strategies – surpassed the main benchmark against which they compare themselves. For active US equity funds, the performance was even worse, with only 29% above their benchmark when adjusted for commissions. Given this track record, benchmarking the index rather than trying to beat it seems like a smarter investment strategy.

Note: The only exception to the trend towards low returns on active funds in 2019 was the non-US stock category: 53% of these fund managers outperform their index.

Low Costs: Because index funds are much easier to manage than their active counterparts, their fees are generally lower. And lower fees mean that investors can hold more of the invested money in their accounts. The annual spending rate of index funds in some large fund companies is below 0.05%. And to encourage clients to start investing in the company, Fidelity Investments offers four index funds that have no management fees at all.

Tax efficiency: Because they sell assets less often than their actively managed counterparts, index funds tend to have a lower distribution of capital gains. Capital gains occur when investments are sold at a price higher than the price at which they were purchased and the federal government taxes them. Less capital gains make this investment option more tax efficient.

Warning: The tax rate is higher for assets held for a year or less that are considered short-term capital gains.

Wide diversification: An investor can get the return on a large segment of the market in one index fund. Index funds often invest in hundreds or even thousands of holdings, offering diversification to balance risk and reward, whereas actively managed funds tend to invest in far fewer companies. You can access many different types of investments by purchasing only a few index funds.

More about cons

There are two major drawbacks to indexing funds:

There is no exact match to index returns: Index funds can never match their target exactly due to the fees charged. Index funds can lag behind their benchmarks as a result of tracking error. This issue can be caused by the components of the target not being counted according to their weights in the index.

Market capitalization can cause a sharp drop: Another drawback of index funds that track a capitalization-weighted stock index is that during market downturns, investors are more exposed to the stocks most likely to fall the most – those that rose most during the prior growing market.

Index Funds or Mutual Funds

The terms “Index Fund” and “Mutual Investment Fund” are not used interchangeably. The main difference is that the first term refers to the purpose of the investment, while the second refers to its structure.

An Index Fund is a fund whose purpose is to track the market index. Its structure can be a mutual fund or ETF. In contrast, a mutual fund is a company that collects money from several investors and uses it to buy stocks, bonds and other securities to build a portfolio of investments. Investors’ shares in a mutual investment fund represent a portion of these investments.

Unlike index funds, the investment goal varies by mutual fund and does not necessarily track the index’s performance. For example, with equity funds, the goal is often to achieve above-average returns that potentially exceed the returns of a market index.


Q: Is it good to invest in index funds?

-If you have no confidence in your fund manager, you want to invest in equity mutual funds. Then you have a great opportunity to invest in index funds. In an index fund, you have got four opportunities;

  1. No fund manager risk
  2. Lesser portfolio churn
  3. Low expense ratio
  4. Traded on exchanges    

Q: Are Index Funds Good for beginners?

– Investors are promised ownership of stocks as well. That is why many shareholders, especially beginners, want to invest in individual stocks in index funds. This is popular among beginners because of its low risk and low price.

Q: Can you lose all of your money in an index fund?

– If you invest your money in an index fund, then there is almost no chance to lose all of its worth. Because the investors will not profit much in the individual stocks so that reasons the index funds risk is quite low.      

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