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

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.

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.

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.

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.

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.

AI investment may be the next major economic bubble

A video examines the massive surge in AI spending—forecast to hit $500B by 2026—and how this may be propping up a fragile US economy. Experts warn that if AI investment slows or under-delivers, the consequences could be felt in markets, jobs and growth.

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 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).

OpenAI CEO Sam Altman has called OpenAI 'the most capital-intensive startup in history'

As of 2024, Silicon Valley was set to spend $1T in the coming years building AI. As companies, including Google and Microsoft, fling billions at AI dreams, concerns are rising about whether that money will ever be recouped. To learn about the argument that there is an AI bubble—and that it could soon burst if AI doesn't prove its worth—read this article.

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.

See a web of circular investments among major AI industry players like Nvidia and OpenAI, as many top AI companies provide significant investments to one another.

71% of equity investments in Q1 2025 went to AI companies

That's up from just 14% in 2020, according to JPMorgan, which recently conducted an analysis of venture capital investment trends in the US.

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.

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.

In 2025, American tech companies will spend $300B to $400B on AI

That is, in nominal dollars, more than any group of companies has ever spent to do anything. Notably, these companies are not remotely close to earning $400B on artificial intelligence.

Google’s CEO has warned that today’s AI boom shows ‘elements of irrationality’

An interview with Alphabet CEO Sundar Pichai warns that the trillion-dollar surge in AI valuations may contain clear signs of irrationality, echoing past tech bubbles. He says no firm—including Google—would be immune if the boom cools or bursts.

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

In 2025, sovereign wealth funds invested more than $66B into artificial intelligence

Developing artificial intelligence, both from a hardware and software perspective, is time and resource-intensive. Sovereign wealth funds, particularly those in the Middle East, have heavily invested in critical AI infrastructure, like data centers.

Many of the top companies in the US by market cap began as tech startups

Combined, the top seven companies by market cap in the US as of December 2024—Apple, Nvidia, Microsoft, Alphabet, Amazon, Meta, and Tesla—were worth more than $16T at the time.

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.

Listen to Palantir CEO Alex Karp's outlook for how AI will change the economy.

Visualizing the AI investment wave

This data visualization from Reuters shows how massive AI investment has become by December 2025—revealing that, in today’s dollars, spending has surpassed the combined total of the Apollo program and the Manhattan Project.

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.

Warren Buffett has worried that AI might end up being as consequential as the development of the nuclear bomb

Berkshire Hathaway chairman Warren Buffett is one of the many people who’ve come face-to-face with the downside effects of AI, and in particular, deepfakes. He was recently shown a deepfake of himself in a video, which caused him to worry about how bad actors will take advantage of the technology.

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.

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.

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.

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.

Hear what Michael Burry thinks about the possibility of an AI bubble

Since his success shorting subprime mortgage-backed securities in 2008, Burry's positions have often become influential, sparking conversations on platforms like X. In 2025, Burry drew attention for betting against Nvidia and Palantir for being overvalued companies.

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 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.

Artificial intelligence might make companies too efficient—which could trigger deflation

AI innovation will likely decrease costs for companies and lead to a large increase in supply. That dramatic increase could conceivably bring prices down but keep supply high. However, AI's real impact will likely be complicated by its impact on human labor and the cost of new technology.