Top 25 Stocks in the S&P 500 By Index Weight For October 2024

The S&P 500—the Standard & Poor's 500 Index—is considered to be one of the best measures of U.S. stock market performance, tracking 500 of the largest and most stable publicly traded companies in the country. The top 25 stocks in the S&P 500 by weight represent the largest, most influential companies in the index. The index is weighted by market capitalization, giving more significance to companies with larger market values.

As of Sept. 24, 2024, the S&P 500 (SPY) was up 18.5% since the beginning of the year. Following a mid-September interest rate cut by the Fed, the index hit a new high by Sept. 24.

The most actively traded components of the big cap index are having a good year. Microsoft (MSFT) is up by 15% so far in 2024. Amazon (AMZN) has increased by 22%. Alphabet Class A (GOOGL) is up 15.27%, while Meta Platforms (META) has gained 37.8% so far this year.

Benefitting from great demand for its artificial intelligence chip designs, Nvidia (NVDA) is on quite a tear, now up 58.7% since the beginning of the year. With a new iPhone model coming out, Apple (AAPL) has gained 18.50% so far in 2024, and retail giant Walmart (WMT) is up 35%.

How are Stocks Selected for the S&P 500?

To be included in the S&P 500, a company must:

• Be a U.S.-based company and trade on a major U.S. exchange
• Have a market cap of $15.8 billion or more and a float-adjusted market cap of at least 50% of the index's total company-level minimum market capitalization threshold
• Have reported positive earnings in the most recent quarter, along with the past four consecutive quarters
• Have a float-adjusted liquidity ratio of 0.75 or greater
• Have traded a minimum of 250,000 shares in the previous six months before evaluation

The S&P 500 reconstitutes each June. Companies removed from the index are not replaced until the next annual reconstitution.

Top Sectors in the S&P 500

The table below lists the S&P 500's top sectors by weighting as of Sept. 24, 2024. The information technology, financials, healthcare, and consumer discretionary sectors carry a cumulative weight of about 67.4%. Meanwhile, the least-weighted sectors include energy, utilities, and real estate—which have a combined weight of just 8.37%.

Top 25 Companies by Index Weight

These are the top 25 companies by index weight. Since the S&P Global website fails to disclose the weighting of component stocks, we used the S&P 500 exchange-traded fund (ETF), the SPDR S&P 500 ETF Trust (SPY), in order to cite index weighting. The ETF's holdings are a bit different, but SPY closely reflects the S&P weights.

As of Sept. 24, 2024, here are the largest SPY holdings by weight:

Why Are the S&P 500's Top 25 Stocks Important?

Analyzing the top 25 stocks of the S&P 500 by index weight sheds light on the health of the stock market and broader economy. Since these companies make up a significant part of the index, they reflect the performance of key sectors, major companies, and the benchmark itself. Several factors have played a role in the outsized performance of tech names—a resilient GDP, combined with declining inflation, strong margins, and competitive positions leading to cash flow generation, emerging trends such as AI, and safety in the face of an economic downturn given their size.  

How Do I Invest in the S&P 500 Index?

There are several options when considering an investment in the S&P 500, spanning a wide range of risk tolerances and investment styles. ETFs—like the SPDR S&P 500 ETF Trust (SPY), iShares Core S&P 500 ETF (IVV), and Vanguard S&P 500 ETF (VOO)—are popular due to their low costs and ease of trading, behaving like stocks on the exchange. For a more traditional approach, index funds, such as the Vanguard 500 Index Fund (VFIAX) and Fidelity 500 Index Fund (FXAIX), offer a way to invest in the S&P 500, though they are traded only once per day at the market's close. For those interested in more complex strategies, derivatives like options and futures, including E-mini S&P 500 Futures, allow speculation on the future value of the index.

Advantages and Disadvantages of Investing in the S&P 500 Index

Investing in the S&P 500 Index offers key advantages, such as exposure to 500 of the largest U.S. companies, providing a diversified portfolio in a single investment. This diversity typically reduces risk compared to investing in individual stocks. Additionally, the historical performance of the S&P 500 has shown consistent long-term growth, making it a favored choice for investors
with a long-term horizon who can wait out market volatility.

However, a notable disadvantage is its heavy concentration in the top names, which could skew performance toward certain sectors or companies, potentially increasing risk. For example, the S&P 500 Equal Weight Index—a version of the S&P 500 index where each of the constituent companies has an equal weight, regardless of their market capitalization—is up 9.92% over the past year compared to the S&P 500’s 19.23%. That said, as analysts have begun to lift their S&P 500 forecast based on upbeat profit revisions, the performance differential between the S&P 500 and its equal-weight counterpart should continue to narrow.

The Bottom Line

The S&P 500 weights constituent companies by market cap, meaning larger firms carry significantly more weight than those with small market values. As a result, tech giants, such as Apple, Microsoft, Nvidia, and Amazon, greatly influence the index's performance. Investors closely follow the S&P 500's top 25 stocks by index weighting to gauge the health of the stock market and the broader U.S. economy.

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As of the date this article was written, the author does not own any of the above securities.