Wealthy PotFXAIX vs VTSAX: The S&P 500 or the Whole Market, Fidelity or Vanguard
FXAIX is Fidelity's S&P 500 index mutual fund at 0.015% a year with no minimum. VTSAX is Vanguard's total U.S. stock market mutual fund at 0.04% with a $3,000 minimum. Both are mutual funds, so they trade the same way. The difference is what they own: FXAIX holds about 500 large companies, VTSAX about 3,500 companies of every size. The 500 are most of the market by value, so the two overlap by 86.3% on our holdings match. Over the ten years to 30 September 2026, FXAIX returned 15.32% a year and VTSAX 14.69%, because large companies did better than small ones over that stretch. That is a record, not a promise. For most people the deciding factor is simpler: which brokerage holds your account.
Table of Contents
The Short Answer
- Overlap: 86.3%. 99.7% of FXAIX's money sits in companies VTSAX also owns. Those companies make up 87.6% of VTSAX; the other 12% or so is the mid-sized and small companies FXAIX leaves out.
- Fees: FXAIX 0.015%, VTSAX 0.04%. On $10,000 that is $1.50 a year against $4.00.
- Minimums: none for FXAIX, $3,000 to open VTSAX (then $1 for later purchases).
- Ten years to 30 September 2026: FXAIX 15.32% a year, VTSAX 14.69%. Both tracked their own index to within 0.01 points.
- Same wrapper. Both are mutual funds that price once a day after the market closes.
- Pick the one your broker sells cheaply. FXAIX at Fidelity, VTSAX at Vanguard. Owning both adds little, because VTSAX already contains nearly everything in FXAIX.
How Much They Overlap
FXAIX's prospectus says it normally invests "at least 80% of assets in common stocks included in the S&P 500® Index." VTSAX's index "represents 100% of the investable U.S. stock market." So every S&P 500 company is also inside VTSAX, along with about 3,000 smaller ones.
Our Portfolio Overlap Checker puts the overlap at 86.3%, across 497 shared companies. It adds up the smaller of the two weights for every company both funds hold, using each fund's SEC holdings report (Form N-PORT): Fidelity's dated 31 May 2026 and Vanguard's dated 30 June 2026.
| Largest shared holdings | % of FXAIX (31 May 2026) | % of VTSAX (30 Jun 2026) |
|---|---|---|
| NVIDIA | 7.89% | 6.36% |
| Apple | 7.05% | 5.87% |
| Alphabet | 6.11% | 5.18% |
| Microsoft | 5.14% | 3.83% |
| Amazon | 4.07% | 3.19% |
The same giant companies lead both funds. VTSAX simply holds them at smaller weights, because it spreads the rest of its money across thousands of companies that are not in the S&P 500. On the same data, FXAIX's ten largest companies were 40.6% of the fund and VTSAX's were 33.4%.
FXAIX vs VTSAX Side by Side
| FXAIX | VTSAX | |
|---|---|---|
| Full name | Fidelity 500 Index Fund | Vanguard Morningstar Total Stock Market Index Fund Admiral Shares |
| Index | S&P 500 | Morningstar US Total Market Index (CRSP US Total Market Index until 29 July 2026) |
| Expense ratio | 0.015% | 0.04% |
| Annual cost on $10,000 | $1.50 | $4.00 |
| Minimum to open | None | $3,000 (then $1) |
| Account service fee | None listed | $25 a year "for certain fund account balances below $5,000,000" |
| Type | Mutual fund, priced once a day | Mutual fund, priced once a day |
| Holdings | 507 (28 Feb 2026) | 3,507 stocks (31 Aug 2026) |
| Ten largest companies | 40.6% (31 May 2026) | 33.4% (30 Jun 2026) |
| Fund size | $749.4 billion (28 Feb 2026) | $2.3 trillion, all share classes (31 Aug 2026) |
| Portfolio turnover | 3% | 3% |
| Inception | 17 Feb 1988 | 13 Nov 2000 |
Vanguard renamed the fund and its index in July 2026 and said the "objective, strategies, and polices remain unchanged." It is the same fund many investors still call Vanguard Total Stock Market.
Returns: Large Companies Have Led
Fidelity and Vanguard both publish quarter-end returns to 30 September 2026, so the comparison below uses the same dates for both funds.
| Average annual return to 30 Sep 2026 | 1 year | 3 years | 5 years | 10 years |
|---|---|---|---|---|
| FXAIX | 15.72% | 22.87% | 13.78% | 15.32% |
| S&P 500 | 15.74 | 22.89 | 13.79 | 15.33 |
| VTSAX | 15.32% | 22.31% | 12.55% | 14.69% |
| VTSAX's benchmark | 15.33 | 22.33 | 12.56 | 14.70 |
| FXAIX minus VTSAX | +0.40 | +0.56 | +1.23 | +0.63 |
| FXAIX, after taxes on distributions | 15.40 | 22.49 | 13.39 | 14.82 |
| VTSAX, after taxes on distributions | 14.91 | 21.90 | 12.15 | 14.23 |
The fee is not why FXAIX led. The fee gap is 0.025 points a year; the ten-year return gap is 0.63. Almost all of the difference comes from what each fund owns. Over this decade the biggest companies beat the rest of the market, and FXAIX holds only big companies. Each fund lagged its own index by about 0.01 points a year, so both did their job.
This can reverse. In years when mid-sized and small companies do better than the giants, VTSAX's extra 12% helps it. Nobody can tell you in advance which kind of decade comes next, which is the main argument for owning the whole market.
The prospectuses show the same pattern over the ten years to 31 December 2025: FXAIX 14.81% a year, VTSAX 14.24%. After taxes on distributions, 14.30% against 13.78%.
| Hypothetical $10,000 held for 10 years | Ending value |
|---|---|
| At VTSAX's 10-year return (14.69%) | $39,378 |
| At FXAIX's 10-year return (15.32%) | $41,595 |
| Difference | about $2,217 |
This is educational information, not personalized investment advice. Past performance does not guarantee future results, and all investing carries the risk of loss.
Where They Really Differ
1. Coverage. FXAIX is a large-company fund. VTSAX adds mid-sized, small and micro-cap companies. If you hold FXAIX alone, you skip about an eighth of the U.S. market by value. Some investors fill that gap with an extended-market fund; others just hold a total market fund.
2. Cost. 0.015% against 0.04% is $25 a year on every $100,000. Real, but small next to the effect of coverage on returns in either direction.
3. Getting started. Fidelity's prospectus says "There is no purchase minimum for fund shares." Vanguard's says the minimum to open an Admiral Shares account "is generally $3,000." If you are starting with $500, FXAIX lets you begin now; for the same total-market exposure without a minimum at Vanguard, its ETF share class VTI needs only the price of one share (see VTSAX vs VTI).
4. Where you can buy it. Each fund is built for its own company's platform. FXAIX's prospectus warns that "you may be charged a transaction fee if you buy or sell shares through a non-Fidelity broker." Other brokers set their own terms for VTSAX. Check your broker's fee schedule before buying the other company's fund.
Which One Fits You
Your account is at Fidelity: FXAIX, or Fidelity's own total market fund. If you want the whole market at Fidelity, FSKAX does at Fidelity what VTSAX does at Vanguard, also at 0.015%; see FSKAX vs FXAIX and FSKAX vs VTSAX.
Your account is at Vanguard: VTSAX if you have $3,000 to start, or VFIAX if you specifically want the S&P 500 there.
Your 401(k) offers only one of them: use the one on the menu. A plan can only offer what it lists, and either fund is a sound core holding.
You want one fund for all of U.S. stocks: VTSAX, or another total-market fund. That is the case for it, regardless of the last ten years.
You already own one in a taxable account: keep it. Selling to switch can realize capital gains that cost more than the fee or coverage difference is worth. Check your 2026 tax bracket first.
Should you hold both? It works, but it is mostly double-counting. Holding both just tilts your portfolio a bit more toward large companies than VTSAX alone would.
Sources & Methodology
- Fidelity 500 Index Fund Summary Prospectus, 29 April 2026: 0.015% fee, no purchase minimum, strategy, returns to 31 December 2025.
- Fidelity Concord Street Trust, Form 485BPOS filed 24 April 2026: FXAIX's full prospectus, including the non-Fidelity broker fee warning.
- Fidelity Concord Street Trust, Form N-CSR for the year to 28 February 2026: FXAIX fund size, holdings count and turnover.
- Fidelity's FXAIX performance page: quarter-end returns to 30 September 2026.
- VTSAX Summary Prospectus, 28 April 2026: 0.04% fee, $3,000 minimum, $25 account service fee, returns to 31 December 2025.
- Vanguard supplement dated 29 July 2026: the Morningstar renaming.
- Vanguard's VTSAX profile: quarter-end returns to 30 September 2026, holdings count and fund size.
- FXAIX Form N-PORT for 31 May 2026 and Total Stock Market Index Fund Form N-PORT for 30 June 2026: the holdings behind the overlap and top-ten figures.
How the overlap was computed. The Portfolio Overlap Checker sums the smaller of the two weights for each company held by both funds, using each fund's latest N-PORT in our dataset. The two filings are a month apart; we state both dates rather than adjust either one.
What we could not verify. Whether a particular broker sells the other company's fund, and at what fee, and which 401(k) plans offer either fund. Fidelity and Vanguard classify sectors differently, so we do not compare sector weights.
This article is for general education and is not investment, tax or legal advice. Past performance does not guarantee future results, and all investing carries the risk of loss. Figures were checked against the sources above on 5 October 2026; verify current figures with each fund company before acting.
FAQ: FXAIX vs VTSAX
Is FXAIX the same as VTSAX?
No. FXAIX holds the S&P 500, about 500 large companies. VTSAX holds the whole U.S. market, about 3,500 companies. They overlap by 86.3% because the large companies are most of the market's value.
Which is cheaper, FXAIX or VTSAX?
FXAIX, at 0.015% a year against 0.04%. That is $15 against $40 a year on $100,000.
Which has performed better?
FXAIX, over the last decade: 15.32% a year against 14.69% over the ten years to 30 September 2026. The reason is that large companies beat smaller ones in that period. That has not always been true and may not be in future.
Does FXAIX have a minimum?
No. VTSAX needs $3,000 to open an account, then $1 for each later purchase.
Can I buy VTSAX at Fidelity or FXAIX at Vanguard?
Sometimes, but you may pay a transaction fee or find the fund unavailable. Each is cheapest at its own company. Check your broker's fund list and fee schedule.
Should I hold both FXAIX and VTSAX?
There is little reason to. VTSAX already contains every S&P 500 company. Holding both mainly adds weight to large companies.
Which is better for a Roth IRA?
Whichever your Roth's broker offers without a fee. Inside a Roth, taxes on distributions do not matter, so the choice comes down to coverage, cost and access.
Cite This Page
Journalists, educators and bloggers are welcome to cite this comparison. Please link back so readers can reach the underlying filings.
"FXAIX vs VTSAX: The S&P 500 or the Whole Market, Fidelity or Vanguard." Wealthy Pot, 2026. https://wealthypot.com/fxaix-vs-vtsax/
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