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 how index funds work and how to choose the best index funds for your portfolio.

What Are S&P 500 Index Funds?

S&P 500 index funds are mutual funds or exchange-traded funds (ETFs) that passively track the Standard and Poor's 500 index. This index represents approximately 500 of the largest U.S. companies, as measured by market capitalization. This means that the largest companies receive the highest allocation in the index.

How to Find the Best S&P 500 Index Funds

There are three primary qualities to look for when searching for the best S&P 500 index fund to buy: 1) Low expenses, 2) performance that closely tracks the index, and 3) high assets under management.

Look for the Lowest Expense Ratios

Keeping investment costs low may be the most important aspect of index fund investing, especially when comparing funds that track the same index. This is because, when comparing funds that track the same index, the funds with the lowest expense ratios generate the best returns over time. 

For example, if an index fund has an expense ratio of 0.50% but a fund that tracks the same index has an expense ratio of 0.10%, the latter fund has 0.40% advantage over the one with the higher expense ratio.

Look for S&P 500 Index Funds with High AUM

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. Low AUM can translate to wider swings in the so-called bid/ask spread. This increases price volatility, which can be a disadvantage for investors.

Look for Low Index Tracking Error

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.

The 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:

  • Vanguard 500 Index (VFIAX): The first index fund available to individual investors, Vanguard's 500 Index fund is the indexing pioneer. Investors wanting to use a mutual fund to invest in the S&P 500 are a good fit for using VFIAX. Fortunately, Vanguard made VFIAX, it's Admiral Shares fund, available to investors. This share class has a lower expense ratio (0.04%), compared to the older Investor Shares fund. 
  • SPDR S&P 500 (SPY): This was the first ETF listed in the United States (January 1993). At $258 billion in AUM, it's also among the largest ETFs trading on the market today. Rounding out SPY's attractive qualities, the expense ratio is low at 0.0945%.
  • iShares Core S&P 500 (IVV): This ETF combines the attractive qualities of high assets under management ($177 billion) and low expenses (0.04%). Investors that want to focus on the low expense ratio can be a good match for IVV.

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, past performance, 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.

Article Sources

  1. Standard & Poors. "S&P 500." Accessed April 10, 2020.

  2. Vanguard. "Index funds: See why Vanguard is still the indexing leader." Accessed April 10, 2020.

  3. Franklin Templeton. "Bid-Ask Spread." Accessed April 10, 2020.

  4. Bogleheads.org. "Tracking Error." Accessed April 10, 2020.

  5. Vanguard. "Vanguard 500 Index Admiral Shares." Accessed April 10, 2020.

  6. State Street Global Advisors. "SPDR S&P 500 Index Trust." Accessed April 10, 2020.

  7. iShares by Blackrock. "iShares Core S&P 500 ETF." Accessed April 10, 2020.