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What are index funds?

Index funds 101: What they are, how they work, and why they're a great option for investors seeking low-cost, diversified portfolios.

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Index funds are an increasingly popular form of investment that offers investors a low-cost, passive way to gain exposure to a broad range of assets. With minimal management fees and no need for active trading decisions, index funds can provide investors with higher returns at lower costs than more traditional forms of investing. 

What is an index fund?

An index fund is a type of mutual fund or exchange-traded fund (ETF) composed of a basket of stocks or bonds that tracks a specific stock market index such as the S&P 500 or Dow Jones Industrial Average. These might also be referred to as index mutual funds.

Unlike actively managed funds, which attempt to beat their respective benchmarks through security selection, index funds strive to replicate their underlying market indexes by holding all (or substantially all) of their components in similar proportions. 

This makes index mutual funds more cost-effective than actively managed funds since they incur fewer trading costs and require less research and fewer management fees. On top of that, since they track established indexes, investors can benefit from the diversification within the asset class without having to pick individual stocks themselves. 

Index funds provide an easy way for investors with any level of experience or resources to access some of the market's best-performing assets at a minimal cost. Index mutual funds are also favored for long-term investment strategies such as retirement funds. 

How do index funds work?

Index funds, also commonly referred to as "indexing", follows a passive form of investing (unlike traditional mutual funds that are typically actively managed funds). Instead of fund managers actively trading a variety of stocks, index funds are built by mirroring the securities of a particular index and holding them. 

The key notion is that by mirroring the profile of the index or stock market, the fund will match its overall performance. For example, over the last thirty years, the S&P 500 has grown an average of 10.7% per annum, which its index mutual fund will mimic.

While the most popular index fund tracks the S&P 500, other prominent index mutual funds include:

The Bloomberg U.S. Aggregate Bond Index

Which tracks the bond market.


Which tracks foreign stocks in Europe, Australasia, and the Far East.

The Dow Jones Industrial Average (DJIA)

Which tracks 30 large-cap companies listed on the stock exchange. 

The index fund portfolio holdings will remain as is unless there is a significant change in the market's benchmark index. Benchmarks are used to measure the performance of the market indexes and will influence whether any changes to the composition of the portfolio need to be made. If changes are necessary, managers will rebalance the percentage of securities as necessary.

Passive vs actively managed funds

Both mutual funds and index funds are great investments, however, they differ slightly in how they operate and the returns one can expect. As with any investment endeavor, investing involves risk.

Actively managed funds

An actively managed investment fund offers investors access to an experienced team of financial professionals or simply a fund manager who makes knowledgeable decisions about where and how to allocate the funds across asset classes. This generally enables larger returns than traditional passive investing.

Typically, many mutual funds are actively managed funds, however, it's best not to assume a fund is actively or passively managed simply based on the fund type. There are plenty of funds that break this rule, like actively managed exchange-traded funds.

The advantages of an actively managed fund are that it can earn higher returns and beat the market index. It's important to note that this is not a guarantee so it's best to check the history of the fund you wish to invest in beforehand and the performance of the team managing it.

It's also worth noting that when the mutual fund sells individual stocks it incurs fees and taxes which will affect the fund's performance. Investors are also required to pay a flat fee despite the performance of the actively managed mutual funds, which could result in the mutual fund underperforming the market index.

Passively managed funds

On the other hand, a passively invested fund mimics a market index and does not have a fund manager or team of fund managers making decisions on what and when to invest.

With passive funds, there are fewer decisions to be made and trades to execute, which allows for less effort and lower fees. Automating the bulk of a passively managed index mutual fund makes it much more cost-effective than paying professionals to determine when and what should be bought or sold.

Typically, an index fund will fall into this category as it does not require full-on management. Once the index on which it will mimic is established, the shares are purchased and the index fund continues with little to no input.

Index funds vs mutual funds

Investors looking to build a portfolio have two popular fund options: index funds and mutual funds. Both types of funds are created by offering diversification through a curated range of stocks and bonds and access to professionally managed investments, but there are some key differences between index funds and mutual funds that investors should be aware of before making their choice. 

Index funds typically carry lower fees than mutual funds, but they also come with fewer features and tend to be more passive in nature. 

Actively managed mutual funds on the other hand provide more flexibility when it comes to customization, as well as access to professionally-managed portfolios which may yield higher returns over time. Understanding how both index and mutual funds work will help investors make an informed decision about which type is right for them.

Is it worth investing in index funds?

Financial professionals will typically agree that index funds are a great way for investors to invest passively in the stock market. Not only do they require little input, but they also offer a low-cost option with a strongly diversified portfolio. Index funds also offer a good investment option for long-term investors.

However, it's important to remember that all investments come with risks, and individual financial situations can vary widely. Before making any investment decisions, it is highly recommended to consult a professional financial advisor who can assess your specific circumstances and provide tailored advice. Their expertise will help you make informed choices aligned with your financial goals and risk tolerance.


This article is for general information purposes only and is not intended to constitute legal or other professional advice or a recommendation of any kind whatsoever and should not be relied upon or treated as a substitute for specific advice relevant to particular circumstances. We make no warranties, representations or undertakings about any of the content of this article (including, without limitation, as to the quality, accuracy, completeness or fitness for any particular purpose of such content), or any content of any other material referred to or accessed by hyperlinks through this article. We make no representations, warranties or guarantees, whether express or implied, that the content on our site is accurate, complete or up-to-date.


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