What Is a Total Market Index?
A total market index attempts to capture the broadest possible cross-section of an equity market. In the United States, that means every publicly traded stock meeting minimum size and liquidity thresholds — from the largest companies in the world down to small-cap businesses that most individual investors have never heard of.
The "total" is a statement of scope. Most familiar indices are partial: the S&P 500 covers roughly 500 large-cap companies representing about 80% of US market capitalisation. The Dow Jones Industrial Average tracks just 30. Sector indices cover one industry. A total market index sets out to cover everything that is investable.
The result is a single measure that reflects the aggregate performance of an entire economy's publicly traded equity — not a curated slice of it.
Full explainer: what is a total market indexMajor Total Market Indices
Several index providers maintain total market indices for the US equity market. They differ in methodology, constituent count, and the funds that track them. The CRSP US Total Market Index — maintained by the Center for Research in Security Prices at the University of Chicago — is the most widely tracked by retail investors, as it underlies Vanguard's VTI and VTSAX.
| Index | Provider | Securities | Coverage | Inception |
|---|---|---|---|---|
| CRSP US Total Market | CRSP / U. Chicago | ~4,000 | ~100% US market | 2012 |
| Russell 3000 | FTSE Russell | 3,000 | ~98% US market | 1984 |
| Wilshire 5000 | Wilshire Associates | ~3,500 | ~100% US market | 1974 |
| S&P Total Market | S&P Dow Jones Indices | ~4,000 | ~100% US market | 2005 |
| MSCI USA IMI | MSCI | ~2,400 | Large/mid/small cap | 1994 |
Total Market Index Funds
Total market index funds track these benchmarks at very low cost. The combined assets in US total market index funds exceed $2 trillion, making them among the most widely held investment vehicles in the world.
| Fund | Ticker | Type | Expense Ratio | AUM |
|---|---|---|---|---|
| Vanguard Total Stock Market Index Fund | VTSAX | Mutual Fund | 0.04% | $1.4T+ |
| Vanguard Total Stock Market ETF | VTI | ETF | 0.03% | $400B+ |
| Fidelity Total Market Index Fund | FSKAX | Mutual Fund | 0.015% | $80B+ |
| Schwab Total Stock Market Index Fund | SWTSX | Mutual Fund | 0.03% | $20B+ |
Data current as of April 2026. Subject to change. Verify current figures with fund providers before investing.
See all total market index fundsTotal Market Index vs S&P 500
Every investor who has heard "just buy an index fund" eventually asks: total market or S&P 500? The S&P 500 covers approximately 500 large-cap US companies — about 80% of total US market capitalisation. A total market index adds mid-cap and small-cap stocks, the remaining 20%.
Historically, the performance difference has been small. Over most long-term periods, the two have tracked within a fraction of a percent of each other annually. The total market argument is completeness: you own everything, with no exposure to the risk of underperforming the true market. The S&P 500 argument is simplicity: the largest companies dominate returns anyway.
Neither is a wrong choice. The differences are real but modest. The decision is a matter of philosophy as much as expectation.
Read the full comparisonHistory
The total market index concept dates to 1974, when Wilshire Associates created the Wilshire 5000 — the first index attempting to capture every publicly traded US stock. It was named for the roughly 5,000 companies it originally tracked; that number has since fallen below 4,000 due to corporate consolidation and a long-term decline in the number of US public companies.
The first total market index fund for retail investors launched in 1992: the Vanguard Total Stock Market Index Fund, tracking the Wilshire 5000. In 2012, Vanguard switched its index provider from Wilshire to CRSP. The fund — now VTSAX — became the most widely held mutual fund in the United States by assets.
Full history of the total market index