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.

The Vanguard Total Stock Market Index, was worth roughly $1.47T as of February 2024

That fund (and the other seven largest mutual funds by assets) is an index fund, meaning it invests in a specific set of preset securities.

90 percent of active managers of large public funds underperform

High fees tend to eat away at whatever edge professional managers accrue, resulting in most such funds performing worse than their underlying benchmark indexes like the S&P 500.

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.

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.

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.

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.

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.

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.

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

In the early 2000s, Warren Buffett invested $1M in an index fund to show that passively managed investments would outperform hedge funds—making the point that actively managed funds are not worth the management fees they charge.

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

Apollo Global Management and Blackstone are among the world's top 20 private credit fund managers

While Blackstone is the world's largest alternative asset manager, Apollo Global Management is a large private equity firm. Apollo had $480B in private credit assets under management as of January 2025.

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.

Active investors try to 'beat' the stock market's performance

There are two primary types of investment strategies that professional investors use: active investing and passive investing. While active investors try to "beat" the stock market's performance, passive investors have a bit more faith in the system.

Activist investors use large ownership positions to influence companies

By holding large ownership positions, which often come with leveraged access to a company's board or the ability to force a shareholder vote, activist shareholders can change a company's corporate governance, leadership, and overall direction. Critics argue that activist shareholders hurt companies in the long term by prioritizing short-term higher shareholder returns over sustainability and growth efforts.

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.

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.

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 world’s top 10 hedge funds

The world’s top 10 hedge funds based on total assets under management include Ray Dalio’s Bridgewater Associates and Citadel.

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.

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.

Mutual fund share classes are rankings of different types of services for investors

The more services an investor has, the more expensive of a class they’re in. While investors are all technically investing in the same securities with the same investment strategy, different classes dictate extra services and attention given to investors, which can seriously impact an investor’s returns.

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 wealthiest Americans own the vast majority of the stock market

Recent data from the Federal Reserve shows that the richest people in America own 93% of all the country's stock—the highest level ever recorded. Meanwhile, the bottom 50% of Americans held just 1% of all stocks.

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.

Can random investments outperform managed funds?

The biggest selling point of mutual funds is they're usually actively managed. Depending on your investment strategy, this could be a breaking point. This podcast episode includes a conversation with a Wall Street Journal columnist about why one-off investments are sometimes better for your portfolio than an actively managed investment.

Mutual funds are categorized as stock, bond, money market, and target-date funds

Each category has even more varieties of funds to choose from, but the biggest differences between these groups are the types of securities they invest in, their risks, returns, and entrance requirements.

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.

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).

See a list of 2024’s top 10 VC firms

A list of the top 10 VC firms, like Sequoia Capital and Andreessen Horowitz, ranked by assets under management shows how those two firms stack up against their competitors—and what kinds of companies those competitors invest in.

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.

BlackRock says investor demand and improvements in underlying fund technology have supercharged ETF availability in 2025

Investors are likely most familiar with ETFs that invest in an index or other grouping of stocks. However, BlackRock breaks down a wide variety of options, including commodity ETFs, currency ETFs, and bond ETFs.

Mutual funds are a type of shared investment strategy that pools money

Mutual funds can invest in stocks, bonds, or other types of securities. This method is a popular way for investors to diversify their portfolio with less risk, making it ideal for long-term financial goals (like retirement).

ETFs vs. mutual funds: Which are better investments?

Exchange-traded funds and mutual funds have many similarities. They both invest in multiple companies under one fund and trade using the same securities (such as stocks and bonds). However, they have distinct differences—such as fees and management style—that can impact your bank account in the long term.

Hedge funds make money from imposing steep fees on investors, as well as from investment performance

Hedge funds often operate on a "2 and 20" model: Investors pay fund managers a 2% management fee, and the hedge fund keeps 20% of their profits. (The 2% is imposed annually, irrespective of performance.) Hedge funds are known for chasing big returns—and taking big risks to get them. This explainer not only breaks down how they work in detail, but also the strategy first introduced in 1949 that still shapes hedge fund investing today.

'The stock market' can be loosely defined as a set of exchanges and other places where shares of public companies are bought and sold.