The Best S&P 500 Index Funds

How to Choose the Best S&P 500 Index Funds for Your Portfolio

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The best S&P 500 Index funds are generally those that have the lowest expense ratios. However, in addition to low costs, there is a delicate balance of science and art to indexing that makes only a few mutual funds and ETFs qualify to make our list of the best index funds. Also learn about indexing how to choose the best index funds for your portfolio.

Keeping Costs Low With Index Funds

Keeping investment costs low is the aspect of index fund investing that most investors know to be crucial to producing the best index funds. Essentially, all other things being equal, the index funds with the lowest expense ratios generate the best returns over time. This can also be an advantage of using index funds as opposed to actively managed funds.

For example, if an index fund has an expense ratio of 0.12 but a comparable actively managed fund has an expense ratio of 1.12, the index fund has an immediate 1.00% advantage over the actively managed fund. Because index funds are passively managed (they simply match the holdings of a given index), the costs of managing the fund are dramatically reduced. With no real research required, costs can be kept extremely low, which has a positive impact on returns over time.

Look for Low Index Tracking Error

Now we are getting into the science of indexing. Investment analysts put together indexes (various lists of stocks or bonds) to create benchmarks for the purpose of measuring broad market averages. The best-known indexes are the Dow Jones Industrial Average, the S&P 500 and Nasdaq. Index funds seek to mirror the performance of a particular benchmark index. For example, most large-cap stock funds try to beat the best-fit index for large-cap stocks, the S&P 500.

However, the objective of an S&P 500 Index fund is not to "beat the index" but to match it, which means the fund will attempt to replicate the performance of the index. To do this, put simply, the fund will hold the same stocks found within the S&P 500. Therefore, the best stock index funds will do a good job of matching the list of stocks (holdings) represented in the benchmark index. Stock analysts may call this "low tracking error."

Weighting Methods With Index Funds

There is more to building an index fund than simply buying the securities represented in the index. To create an index fund, and ensure good performance tracking, the management team and supporting staff will determine how much (the number of shares) of each holding on the list to purchase.

The idea is to match the percentage "weighting" of the index itself. Indexes that rank the holdings so that the larger components are given larger percentage weights are called capitalization-weighted indexes (aka cap-weighted or market cap weighted indexes).

The S&P 500 is an example of a cap-weighted index. Most index funds will mirror the cap-weighted index by buying shares of holdings to make the stocks with the largest capitalization the largest holding by percentage in the index fund. For example, if XYZ Corporation stock has the largest market capitalization, XYZ Corporation stock will represent the largest percentage of the index fund.

Size Matters With Index Fund Investing

In the indexing world, size can matter. An index fund with high assets under management (AUM) is not only an indication of quality but also an advantage, especially when it comes to liquidity in ETFs. By comparison, an index fund with a low amount of assets may find difficulty in keeping the portfolio properly weighted to the index.

Large mutual fund companies, such as The Vanguard Group, Fidelity Investments, and Charles Schwab have large numbers of investors and therefore they have the assets to effectively manage the fund (i.e. buy shares of holdings, provide liquidity to meet the demand for investor withdrawals).

Top 3 Best S&P 500 Index Funds

Now that you know what it takes to make the best index funds, you can select the best S&P 500 Index Funds for your portfolio:

Here are three of the best S&P 500 index funds on the market today:

  • Vanguard 500 Index (VFINX): Vanguard was built upon indexing and is the original in the world of index funds. Forty-five years ago, Vanguard founder, John Bogle, observed that the majority of stock investors were unable to outperform the S&P 500 Index consistently over long periods of time. His idea was to simply match the holdings of the index and keep costs low. Simplicity and frugality are two of the greatest tenets of successful investing and Vanguard has these virtues mastered. Vanguard is also owned by its investors, which places its priorities on providing high-quality, low-cost mutual funds and ETFs, as opposed to a culture of high profits typical of some publicly owned financial institutions.
  • SPDR S&P 500 (SPY): This was the first exchange traded fund listed in the United States (January 1993). Investors use SPY because it offers a wide range of large U.S. companies with a single purchase. This high-volume ETF combines stock from companies with a market capitalization of $5 billion or greater in one diverse portfolio, and trades almost 16 billion shares per day on average.
  • iShares Core S&P 500 (IVV): This fund is a broadly traded ETF that tracks the S&P 500. Investors are usually attracted to IVV because they can get S&P 500 exposure at a low holding cost. This ETF trades on average 850 million shares everyday. IVV combines the largest capitalization U.S. stocks in one portfolio, and focuses on tax efficiency and long-term growth. 

Tips for Buying Funds With Low Expenses

If you are fortunate enough to have high balances in your investment accounts, you may qualify for other share classes that have even lower expense ratios than those funds listed here. For example, Vanguard has another share class, called Admiral Shares, that provide lower expense ratios.

Bottom Line

The best S&P 500 index funds are generally those with the lowest expense ratios. However, investors are wise to watch for other qualities, such as assets under management, weighting methods, and tracking error. S&P 500 index funds can make good core holdings in a portfolio but they may not be right for all investors.

Disclaimer: The information on this site is provided for discussion purposes only, and should not be misconstrued as investment advice. Under no circumstances does this information represent a recommendation to buy or sell securities.