The S&P 500 selection committee has strict rules around adding a company to the index

Listen to the methods and strategy of the secretive S&P 500 selection committee

Stocks are added to the S&P 500 by a secret selection committee that meets regularly to assess which companies can remain in the index, which companies need to be added, and which companies no longer meet the criteria. The members of the committee used to be public, but S&P Global decided to keep its members confidential after companies sent packages, letters, and gifts to try to make it into the index.

Before the S&P 500 launched in 1957, Standard and Poor's had a daily index with just 90 companies

Unlike previous indexes from S&P, the S&P 500 could be computed in real time using computer technology that tracked stock tickers across stock exchanges. This innovation is partly what led to 500 companies being listed on the index, a huge increase from the 90 companies in S&P's flagship index when the company had to do all the analysis by hand.

The S&P 500 is composed of 500 companies, but has more than 500 total listings

Since some large companies have dual-class stock structures (like Alphabet and Fox Corporation), there are multiple listings on the S&P 500 for the same company. S&P Global has banned and then reversed bans on companies with dual-class structures multiple times since first allowing dual-class stocks in 2014.

S&P Global, the company that makes the S&P 500, is listed on the S&P 500

When the S&P 500 index was released in 1957, it was helpful for investors, but not necessarily profitable. S&P Global now makes more than $1B a year just from selling its index data. Alongside its other services, like credit ratings, S&P Global makes more than $14B a year.

Watch how the S&P 500 is actually calculated

After accounting for each company's float-adjusted market capitalization (a metric that combines the price of a company's stock, the total number of shares, and the stock's float, which means how many shares are actually available), the S&P 500 formula uses a divisor to create the index number. However, what the divisor is and what it represents are secrets.

A 'large-cap' company has a market capitalization of more than $10B

The S&P 500 is primarily composed of large-cap companies. The idea is that the index provides a big-picture view of the economy by assessing the performance of many of the largest public companies across different industries. The median market capitalization of companies listed on the S&P 500 is around $40B.

Dow components are chosen by a committee, not a formula

Unlike many indices, the Dow has no strict rules for inclusion. A small committee at S&P Dow Jones Indices uses judgment—favoring companies with strong reputations, steady growth, and broad investor interest.

Some argue that the S&P 500 is actually an actively managed index

Some critics of the S&P 500's selection process argue that human involvement makes it an actively managed index. S&P Global maintains that while a human selects the stocks in the index, those decisions are not made with the intent of maximizing performance, but rather, to provide a snapshot of the largest companies across different industries.

The S&P 500, managed by the same company, is another major stock index

Also run by S&P Dow Jones Indices, the S&P 500 tracks 500 large US firms using market-value weighting. Many analysts view it as a more accurate gauge of the American economy.

Investors rely on the S&P 500 as a benchmark for the state of the economy

Since the index represents a broad range of diverse industries, it's become a proxy for the market itself and a common benchmark for investors to compare returns and performance patterns against. Generally speaking, when someone says a stock is under- or out-performing the market, that actually means under- or out-performing the S&P 500. The S&P 500 is exchange-agnostic, and includes companies listed on both the NYSE and Nasdaq.

In late 2025, the top 10 companies in the S&P 500 made up more than 40% of the index's total value

This raised concerns for investors about the index's risk exposure. As many large tech companies continued posting record highs, analysts argued that the top-heavy index was becoming less representative of the economy as a whole.

See a timeline of S&P Global's history—the company behind the S&P 500

From the 1941 merger of Standard Statistics and Poor's Publishing to the creation of the S&P 500 in 1957, the company that created the famous index has long been a leader in financial intelligence.

Why some say the S&P 500 has effectively become an AI fund

The S&P 500 is a market-cap-weighted index, which means companies with larger market capitalizations have a larger impact on the index's overall performance. Many of the top companies in the index are currently tech companies—including Nvidia, Microsoft, Alphabet, and Apple—that all have large investments in artificial intelligence. As a result, some analysts are concerned that the index is overly exposed to risky AI investments.

The SPDR S&P 500 ETF is one of the most highly traded funds on the market

State Street, a popular ETF issuer, is responsible for the SPDR S&P 500 ETF. This fund trades under the SPY ticker, and State Street maintains a web page with key facts and figures on SPY. For instance, its expense ratio is 0.0945%, or $9.45 on an initial $10K investment.

The S&P 500 yields a roughly 10.5% average annual return

Tthe factors that go into that calculation are multifaceted—from how inflation impacts it to the stocks themselves. During periods of high inflation, stock performance can be stunted by investor concerns, for instance. The average return also varies based on whether dividends are included.

Read about the evolution of the S&P 500 and its recession recovery

Since the S&P 500 is considered a bellwether index (meaning it represents the health of the US economy), its value is important for investors in both bull and bear markets. The S&P 500 has been impacted by recessions and downturns, from the 1970s oil crisis to the dot-com crash of the early 2000s.

The Dow Jones Industrial Average vs. the S&P 500: Which one is a better representation of the economy?

The Dow and S&P 500 are both indexes meant to provide a broad representation of the economy. The Dow has 30 companies and is weighted by share price, while the S&P 500 has 500 different companies weighted by market capitalization. Since the indexes are so different, investors don't always agree on which index is a better representation of the economy—though the two move in the same direction more than 90% of the time.

Millions of Americans will be invested in SpaceX because of the fast-tracked process to list SpaceX on the Nasdaq 100, and, subsequently, the index funds that track it.

A stock index is a group of companies clustered together, often providing a condensed snapshot of a market segment.

Read about the 'gatekeeper' of the stock market, former index chair at S&P Global

David Blitzer, the former index chair at S&P Global, earned the nickname "gatekeeper" of the stock market after helping decide which companies made it into the S&P 500 for 24 years. Blitzer became a legend in the world of indexing and has a reputation for being even-tempered and always wearing a bow tie.

Vanguard Group founder Jack Bogle created the first index fund, the Vanguard 500, in 1976—but the fund didn't take off until the 1990s.

The S&P 500 has an average intra-year drawdown of -16%

In a given year, the value of the S&P 500 can significantly fluctuate. An intra-year drawdown is the most significant difference between the index's peak and lowest point.

See how the S&P 500 performed throughout the first 100 days of each modern presidency.

Read how Vanguard's founder used the S&P 500 to revolutionize retail investing

John Bogle, the founder of The Vanguard Group, created a fund that tracked the S&P 500 in 1976. That fund created an unprecedented opportunity for individual retail investors, brought down fees across the board, and popularized the belief that passive, low-cost index fund investments would outperform actively managed portfolios long-term.

The Nasdaq Composite index includes all of the companies traded on the exchange

This 3,000+ company index stands in contrast to the Nasdaq 100, which only includes 100 of the most influential non-financial companies traded on the exchange. These are the two most commonly used indices for Nasdaq investments.

S&P 500 stocks that have increased their dividends for 25 consecutive years are called 'dividend aristocrats'

Dividend aristocrats are considered the best of the best on the S&P 500—all with market capitalizations above $3B, more than $5M in daily trading volume, and consecutive dividend growth for a minimum of 25 years. Some examples of dividend aristocrats are Coca-Cola, Procter & Gamble, and Walmart.

The 'Big Three' asset managers—Vanguard, State Street, and BlackRock—collectively manage more than $30T in assets and are the largest shareholders in roughly 88% of all the companies listed on the S&P 500.

Explore a step-by-step guide for getting started as a retail investor

Instead of purchasing individual stocks and bonds, new investors may want to start in funds that track an index—like the S&P 500—or that hold a group of themed stocks.

SPACs, explained

Special purpose acquisition companies make it easy for mature unicorns (companies valued at over $1B) to receive growth capital by going public. This process effectively skips the work of a traditional initial public offering, and its time-intensive investor negotiations. Typically, a well-known investor with expertise in a certain industry sponsors a SPAC with the intent to acquire a startup. Learn how it works and the risks involved here.

The Nasdaq 100 index tracks the exchange's 100 largest non-financial companies

This index was created in 1985, over a decade after the Nasdaq first launched. The companies on the index must meet certain criteria, including having a minimum average daily trading value of $5M.

An S-1 reveals financial and other details to the public, often for the first time, when filing for an IPO

To file for an IPO, a company must file a registration form called an S-1 or prospectus with the US Securities and Exchange Commission. S-1s detail a company's current business model, competitive landscape, and other financial information.

See every company in and out of the Dow since 1928

The index has had 30 companies since 1928. See each company’s tenure on the index and what firms were added or replaced by year and industry.

Find out how companies decide which stock exchange to list on

Tech companies often prefer to list on the tech-focused Nasdaq, whereas more traditional organizations opt for the New York Stock Exchange. Sometimes the choice is made partly based on the services an exchange offers a company.

Visualizing decades of stock market performance

Stock markets and the indexes that track their biggest companies tend to ebb and flow, with long growth periods punctuated by shorter recessions. Track the 60-year history of one of the most common stock market indexes, the S&P 500, with this data visualization. The chart highlights the long-term durability of markets despite appearance of short-term volatility.

The 50-100-500 rule: when a startup is no longer a startup

According to startup expert Alex Wilhelm, a company cannot be considered a startup if it generates revenue exceeding $50M, employs more than 100 people, and has a valuation of $500M or more. However, Wilhelm modified the rule in 2018 to $100M in revenue, over 500 employees, and a valuation of $2.5B or more.

Companies sometimes change which stock exchange they're listed on.

Even iconic companies can get dropped from the Dow

The Dow’s lineup evolves as the economy changes. General Electric, part of the original 1896 index, was removed in 2018, after 122 years. ExxonMobil, once the world’s largest company, was replaced by Salesforce in 2020.

The fees for keeping a company listed on the NYSE are typically higher than the Nasdaq's.

The Nasdaq's 'Magnificent 7' have an outsized impact on the Nasdaq 100's performance

These seven companies are Alphabet, Amazon, Apple, Meta, Microsoft, Nvidia, and Tesla. They're often responsible for over 40% of the Nasdaq 100 index's gains, but the exact percentage varies from year to year.

The number of publicly traded companies has decreased in recent years.

In 1996, more than 7,300 companies traded publicly on US stock markets, but that number has recently dropped to 4,300. Economists point to two reasons: First, going public requires full disclosure of operations, exposing it to scrutiny from investors, competitors, and analysts. Second, the IPO process is expensive and time-consuming.

Ride along on one coffee company's journey through the stock market to better understand how a company goes from private to public.

Critics argue the Dow no longer reflects the modern economy

With only 30 companies and a price-weighted formula, skeptics say the DJIA underrepresents vast sectors of the market. They claim it is outdated, though its close correlation with the broader S&P 500 keeps it relevant.

The Dow now tracks 30 major US companies across various industries

Since 1928, the DJIA has included 30 firms. Today's group spans technology, healthcare, and finance—with Apple, Microsoft, JPMorgan Chase, Pfizer, and Coca-Cola among its most recognized components.

The Dow’s price-weighted formula makes stock price matter more than size

Unlike most indices, which weigh companies by market value, the DJIA is price-weighted—meaning higher-priced stocks have more influence on its movements. As a result, a company’s share price matters more than its overall size.

Index funds are typically structured as either mutual funds or exchange-traded funds, but investors can manually recreate an index through 'direct indexing.'

Learn about the essential Securities and Exchange Commission filing types, including S-1, 10K, 10Q, and 8-K.

Prior to the creation of the Securities and Exchange Commission, the 1913 Pujo Committee determined that 180 people were managing more than $22B—a large slice of the entire nation's wealth—and recommended extensive regulations.

The world's 50 most valuable private companies

While public companies typically have the highest valuations, private companies get close. This list breaks down the top 50 as of 2025, with SpaceX at the top with a value of $350B, followed by ByteDance. Over three-fifths of the list are located in the US, with eight in China.

More than 650 companies went public in the US in 1996

As the dot-com bubble reached its peak, most dot-com companies went public with little proof of being profitable and were often overvalued. In 1999, the Nasdaq's price-to-earnings ratio (a tool used to determine a stock's value that divides its price by earnings) hit 90.2, signaling that many companies were operating at a net loss. Startups promised investors that more time and money would help scale their businesses and become profitable.

An initial public offering is how a private company becomes public.