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

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, 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.

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.

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

While the decision to add a company to the index is ultimately up to the selection committee, any prospective company has to meet some criteria to be considered. To join, the company must have been profitable for the last four quarters, must have a market capitalization exceeding $22.7B, and meet certain requirements around tradeable stock availability (or float).

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.

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.

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.

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.

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.

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 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.

Dual-class stock structures separate equity and decision-making authority

In the past few decades, dual-class stock structures have become an increasingly popular way for companies to raise capital in public markets without allocating traditional shareholder voting rights. Meta, Estée Lauder, and The New York Times are companies that are famously dual-class.

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.

Dozens of S&P 500 stocks, including Coca-Cola and Walmart—known as the dividend aristocrats—have increased dividends every year for 25 years

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.

The Nasdaq's 'Magnificent 7' companies are responsible for roughly 40% of the Nasdaq 100 index's gains, while the remaining 93 companies account for the other 60%.

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.

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.

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.

A direct listing is when a company goes public, listing shares on a stock exchange

A direct listing is when a company goes public, listing its shares on a stock exchange, rather than issuing new shares or raising capital. That means investment banks—traditionally serving as intermediaries—could lose out on some of the profits from these deals as more companies like Spotify opt for direct listings.

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

The current maximum annual listing fee for companies listed on the New York Stock Exchange was $500K as of early 2026. The maximum annual listing fee for companies listed in Nasdaq's top tier, on the other hand, was of $193K. Companies listed must pay these fees each year.

Biotech ETFs allow investors to gain exposure to multiple promising companies in the industry

Biotech ETFs offer a diversified alternative to purchasing an individual biotech stock and gambling on whether an individual company’s clinical trial yields the next blockbuster cancer treatment or an absolute flop. This list of the top biotech ETFs in 2025 can help you learn more about them.

View a list of companies owned by Google's parent company, Alphabet

These companies include Google subsidiaries like YouTube, the biggest online video sharing and streaming platform, Nest, which manufactures smart products like speakers and thermostats, and Waymo, the technology company developing self-driving cars.

Mutual funds vs. stocks: Which are better investments?

Mutual funds invest in multiple different companies with money from many investors, while stocks focus on investing in one company with funds from a single investor. There are pros and cons to both, but the weight of them depends on your personal financial goals.

Over 400 tech companies call Santa Barbara home

The city boasts a strong talent pipeline from UCSB, established tech companies like Sonos and Procore and dozens of startups. Search for any company in Santa Barbara with this regularly-updated directory.

League tables show the number of deals top investment banks do in a time period

These tables provide a visual to help keep track of the leading companies in investment banking. Companies such as JPMorgan and Goldman Sachs typically sit up top.

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

An initial public offering or 'IPO' is the process of a private company becoming public by putting shares of the company on the stock market for purchase.

While the first exchange-traded fund (a 'basket' of different assets that can be bought and sold on a stock exchange) in the US only launched in 1993, the global ETF market has grown to more than $10T in the short time since.

In 2025, four executives from large tech companies were given positions in the US Army Reserves—including Palantir Chief Technology Officer Shyam Sankar, which reinforced Palantir's ties with the US military and its role as a leading defense partner.

The United States is one of only around two dozen countries with a fully federal system of government, in which power is divided between national and state governments.

US consumers collectively owe more than $1T to credit card companies—almost as much as they owe in auto loans.

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

Fast-casual restaurant Chili's is experiencing a resurgence, with its parent company recently reporting a nearly 32% increase in sales, thanks to passionate Gen Z fans on TikTok.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Warren Buffett's former professor Benjamin Graham is known as the 'father of value investing,' a strategy in which investors seek to buy stocks trading below their intrinsic worth.

Up to a million Girl Scouts sell about 200 million cookie boxes every spring, generating $800 million, largely because refusing a child is frowned upon

Hear about the 250-year history of the United States Postal Service, complete with some of its strangest deliveries, important innovations, and the figures that made it an American institution.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Stars appear to twinkle because turbulence in the motion of molecules in Earth's atmosphere causes light to bend and wiggle rapidly on its way to the surface—a phenomenon called scintillation.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

Frank Lloyd Wright's houses are historically hard to sell because they're old, subject to local landmark commissions, and often unfashionable

Explore a list of the 100 best novels of all time, compiled by some of the world's best living writers, including Salman Rushdie, Stephen King, and Jennifer Egan.

US intelligence allegedly pursued more than 600 schemes to assassinate Cuban revolutionary Fidel Castro.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

Search a massive database of over 4 decades of clues from the TV quiz show 'Jeopardy!'

Sony set the standard for cylinder-shaped batteries when it repurposed manufacturing equipment used to make rolls of magnetic recording tape.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

Between 10 million and 50 million people in the US develop rashes from poison ivy, poison sumac, and poison oak each year.