VTSAX vs FZROX vs FSKAX: Which Should You Pick?
FZROX is free, FSKAX 0.015%, VTSAX 0.04%. From 2018 to Sept 2026 FZROX led by 0.14 points a year. Which fits a Fidelity IRA, a taxable account, or Vanguard.
VTSAX, FZROX and FSKAX are the three most popular total U.S. stock market mutual funds. Each owns large, mid and small companies weighted by market value, and each tracks a different index: VTSAX the Morningstar US Total Market Index (called the CRSP US Total Market Index until July 2026), FZROX Fidelity’s own U.S. Total Investable Market Index, and FSKAX the Dow Jones U.S. Total Stock Market Index. They charge 0.04%, 0.00% and 0.015%: $40, $0 and $15 a year on $100,000. Their monthly returns since 2018 have been 0.9999 correlated. What separates them is where you can hold each one and how each is taxed in a brokerage account.
Quick answer
In a Fidelity IRA, Roth IRA or HSA, buy FZROX. It costs nothing, and if you ever move the account you can sell inside it without tax. In a Fidelity taxable account, FSKAX costs $15 a year per $100,000, and its prospectus does not restrict it to Fidelity brokerage accounts the way FZROX’s does; FZROX is the better buy there only if you expect to keep a Fidelity account for that money. At Vanguard, buy VTSAX or VTI, its ETF share class. Fidelity charges $100 to buy VTSAX, so build a VTSAX position at Vanguard. If you already own any of the three with gains in a taxable account, keep it.
| VTSAX | FZROX | FSKAX | |
|---|---|---|---|
| Sponsor | Vanguard | Fidelity | Fidelity |
| Expense ratio | 0.04% | 0.00% | 0.015% |
| Fee on $100,000 | $40 a year | $0 | $15 a year |
| Index | Morningstar US Total Market | Fidelity U.S. Total Investable Market | Dow Jones U.S. Total Stock Market |
| Stocks held | 3,528 | 2,640 | 3,736 |
| Top 10 holdings | 33.45% | 34.97% | 34.74% |
| Minimum | $3,000 at Vanguard | $0 | $0 |
| Where you can hold it | Vanguard; other brokers may charge to buy | Fidelity accounts and certain broker-dealers with Fidelity arrangements | Fidelity, retirement accounts, or through an investment professional |
| ETF share class | Yes: VTI | No | No |
| Capital gains paid, last 10 fiscal years | None | Since 2018 launch: $0.01 to $0.03 a share in 3 years, none after FY2022 | 4 years; none since FY2020 |
| Annual return, Sept 2018 to Sept 2026 | 13.71% | 13.85% | 13.71% |
Expense ratios and minimums from the summary prospectuses (VTSAX April 28, 2026; FZROX December 30, 2025; FSKAX April 29, 2026). Stocks held from each fund’s latest public SEC Form N-PORT (VTSAX June 30, FZROX July 31, FSKAX May 31, 2026). Top 10 holdings from Fidelity’s fund pages (FZROX and FSKAX September 30, VTSAX August 31, 2026). Capital gains from annual reports. Returns are Summitward calculations from month-end total-return prices, August 31, 2018 to September 30, 2026.
FZROX has the best record since its 2018 launch
Over the 97 months from August 31, 2018, the first month end after FZROX launched, to September 30, 2026, FZROX returned 13.85% a year. VTSAX and FSKAX each returned 13.71%. FZROX’s fee advantage explains a small part of its 0.14-point lead: 0.04 points against VTSAX and 0.015 against FSKAX. The rest came from the difference in indexes and in how each fund tracks its own. Securities lending is too small to account for it; FZROX earned $1.8 million from lending in the year to October 2025, about 0.006% of its $31.8 billion in assets.
| Year | VTSAX | FZROX | FSKAX |
|---|---|---|---|
| 2019 | 30.80% | 31.15% | 30.92% |
| 2020 | 20.99% | 20.50% | 20.78% |
| 2021 | 25.71% | 26.01% | 25.65% |
| 2022 | -19.53% | -19.19% | -19.51% |
| 2023 | 26.01% | 26.21% | 26.12% |
| 2024 | 23.74% | 23.94% | 23.88% |
| 2025 | 17.12% | 17.24% | 17.05% |
Total returns from the funds’ prospectuses and annual reports; FZROX 2025 from Fidelity’s performance page.
FZROX was ahead of FSKAX in all 62 rolling three-year periods in the sample and ahead of VTSAX in 58 of them. It trailed VTSAX by 0.49 points in 2020, which is why the four exceptions all include that year. The rolling periods overlap, and eight years contain fewer than three separate three-year spans, so this record cannot tell you whether Fidelity’s index will keep its edge. VTSAX and FSKAX finished 0.002 points a year apart. FSKAX’s lower fee did not show up in its return, and over this period the two were tied.
How much of the market FZROX leaves out
Fidelity’s index starts from the largest 3,000 U.S. companies and then screens out those with less than $75 million of float-adjusted market value, less than 15% of shares freely traded, or less than $25 million of trading over six months. That left FZROX with 2,640 stocks at July 31, 2026. The Morningstar and Dow Jones indexes have no limit on the number of stocks, which is why VTSAX and FSKAX each hold 3,500 or more.
By market value the extra names barely register. In VTSAX’s June 30, 2026 filing, the 883 companies smaller than the 2,615th-largest (the number of companies FZROX held) made up 0.09% of the fund. In FSKAX’s May 31 filing, its 1,083 smallest made up the same 0.09%. That fits FTSE Russell’s estimate that the microcaps below the largest 3,000 U.S. companies are under 1% of U.S. market value. The top 10 holdings are about a third of each fund.
Matching the filings company by company gives a larger figure, because FZROX also skips some bigger names. Companies in VTSAX that were absent from FZROX’s July 31 filing made up 0.51% of VTSAX; for FSKAX the figure was 0.25%. The largest single gap was SpaceX, 0.14% of VTSAX, which listed on June 12, 2026 and was in VTSAX’s June filing but not FZROX’s July one. The filings are one to two months apart, so part of this is timing rather than a lasting difference. Our script and data reproduce both measures.
Taxes in a brokerage account
Every fund here passes its dividends to shareholders. The difference is capital gains distributions, which a taxable investor pays tax on without selling anything. VTSAX paid none in the ten years through 2025. It shares a portfolio with the VTI ETF, and when ETF shares are redeemed the fund can hand out its lowest-cost shares instead of selling them. FSKAX paid capital gains in fiscal years 2017 through 2020, from $0.13 to $0.51 a share, and none in the six years since. FZROX paid $0.01 to $0.03 a share in fiscal 2019, 2020 and 2022. Over the ten years to 2025, the published after-tax returns on distributions were 13.78% for VTSAX and 13.75% for FSKAX, a 0.03-point gap. FZROX’s prospectus reports after-tax figures only through 2024, so it does not line up with the other two. In an IRA, Roth IRA, 401(k) or HSA, none of this matters.
If you might leave Fidelity
FZROX’s prospectus says its shares “are available only to individual retail investors who purchase their shares through a Fidelity brokerage account,” including IRAs, HSAs and BrokerageLink accounts, and “also may be available to certain broker-dealers that have entered into arrangements with Fidelity.” Unless your new broker is one of those, the shares cannot move with you. FSKAX’s prospectus lists more channels, including retirement accounts and investment professionals; ask the new broker whether it will hold FSKAX and what it charges to buy more before you move.
An appreciated FZROX position in a taxable account does not have to be sold when you change brokers. You can:
- Keep a Fidelity account open for the FZROX shares and move everything else.
- Sell in a year when your income is low. For 2026, long-term gains are taxed at 0% federally up to $49,450 of taxable income for a single filer and $98,900 for a married couple filing jointly.
- Give appreciated shares to a charity or donor-advised fund.
- Hold them for life. Heirs receive a stepped-up basis, which erases the gain.
VTSAX has a route the Fidelity funds lack. Vanguard converts VTSAX shares into VTI, the ETF share class of the same fund, and says the conversion is tax-free when both are held at Vanguard. It runs one way only, and other brokers may cash out fractional shares in the process, which is taxable outside an IRA. Whole VTI shares then transfer to any brokerage. Vanguard’s VTI and VTSAX are the same portfolio in two wrappers.
Switching an existing position
In a tax-advantaged account, switching between these funds costs nothing, and the cheaper fee is a reasonable tiebreaker. In a taxable account, the tax on your gains usually outweighs the fee savings for decades. One example: a $100,000 VTSAX holding with $60,000 of cost basis, taxed at a combined 20% on long-term gains (15% federal plus 5% state), costs $8,000 to switch into FZROX. Assuming a 7% annual return and a final sale after 20 years, keeping VTSAX leaves about $16,000 more after tax, and the switch does not catch up within 100 years. Enter your own position below.
Who should pick which
VTSAX
You invest at Vanguard, or you already own it. If you might move brokers someday, VTI is the same fund as an ETF and transfers anywhere. Its capital gains record is the cleanest of the three.
FZROX
You invest in a Fidelity IRA, Roth IRA or HSA, or in a Fidelity taxable account you expect to keep. It has the lowest fee and, so far, the highest return.
FSKAX
You invest at Fidelity in a taxable account and might move it, or you prefer an index run by an outside provider. It costs $15 a year per $100,000.
Frequently asked questions
Is FZROX better than VTSAX?
On returns so far, yes: 13.85% a year against 13.71% from August 2018 to September 2026, after fees. FZROX trailed VTSAX in 2020 and led in the other six calendar years from 2019 to 2025. Which is better for you depends on the account. In a Fidelity IRA, Roth IRA or HSA, FZROX is the stronger pick. In a taxable account you might move away from Fidelity, VTSAX’s record of no capital gains payouts and its tax-free conversion to VTI at Vanguard count for more than its 0.04% fee.
Are FZROX and FSKAX the same fund?
No. Both are Fidelity total-market index funds, but FZROX tracks Fidelity’s own index and held 2,640 stocks at July 31, 2026, while FSKAX tracks the Dow Jones U.S. Total Stock Market Index and held 3,736 at May 31, 2026. FZROX charges nothing and FSKAX 0.015%. Their monthly returns since 2018 have been more than 0.9999 correlated. The practical difference is that FZROX’s prospectus limits it to Fidelity brokerage accounts and certain broker-dealers with Fidelity arrangements.
Can I transfer FZROX to Vanguard or Schwab?
Only if the new broker has an arrangement with Fidelity to hold it, which you should confirm before you start a transfer. Otherwise you can leave the FZROX shares in a Fidelity account and move everything else, or sell them. In an IRA, Roth IRA or HSA, selling costs no tax. In a taxable account, selling realizes your gains, so a year with low income is the cheapest time to do it.
Can I buy VTSAX at Fidelity?
Yes, but Fidelity listed a $100 online transaction fee on each VTSAX purchase and a $2,500 minimum when we checked on October 15, 2026. Regular contributions make that fee add up quickly, so at Fidelity FSKAX or FZROX is the cheaper way to own nearly the same market.
Which one should I use in a Roth IRA?
Whichever your broker offers without a fee. At Fidelity that is FZROX: it costs nothing, and selling inside the Roth to move it later triggers no tax. At Vanguard, VTSAX (with its $3,000 minimum) or VTI.
Does FZROX pay capital gains distributions?
Small ones. FZROX paid $0.01 a share in fiscal 2019, $0.01 in fiscal 2020 and $0.03 in fiscal 2022, and none in fiscal 2023 through 2025. VTSAX paid none in the ten years through 2025. FSKAX paid capital gains in fiscal 2017 through 2020 and none since. In a retirement account none of these payouts are taxed.
Should I sell VTSAX to buy FZROX?
In a taxable account, usually not. The tax on your gains is due now, and the fee saving is $40 a year per $100,000. In the example above, a $100,000 VTSAX holding with $40,000 of gains does not recover the tax within 100 years at a 7% return. In a Fidelity IRA, switching costs no tax, so the lower fee is a reasonable tiebreaker.
Can I harvest a loss by switching between them?
Some investors do, because the three track different indexes. IRS Publication 550 does not say whether index funds on different indexes are “substantially identical,” and no ruling covers these pairs, so the question is unsettled. Our tax-loss harvesting guide covers how to choose partners and the wash-sale rule’s 30-day windows.
Did VTSAX change when Vanguard renamed it?
On July 29, 2026 Vanguard renamed the fund the Vanguard Morningstar Total Stock Market Index Fund, and its index became the Morningstar US Total Market Index after Morningstar bought CRSP. Vanguard’s filing says the fund’s investment objective and strategies did not change. Morningstar Bought CRSP: Did VTI Change? covers the details.
Sources and related reading
- Vanguard Total Stock Market Index Fund summary prospectus (April 28, 2026), July 29, 2026 supplement renaming the fund and index, and 2025 annual report.
- Fidelity ZERO Total Market Index Fund summary prospectus (December 30, 2025), annual report for the year ended October 31, 2025, and fund research page.
- Fidelity Total Market Index Fund summary prospectus (April 29, 2026), annual report for the year ended February 28, 2026, and fund research page.
- Fidelity, Cap Weighted Indices methodology (September 2022); S&P Dow Jones Indices, Dow Jones U.S. Total Stock Market Indices methodology (September 2026); FTSE Russell, Russell US completion indexes overview (data as of April 30, 2026).
- Vanguard, converting mutual fund shares to ETF shares; Fidelity’s VTSAX page (transaction fee and top 10, read October 15, 2026); IRS Publication 550.
- Holdings and return calculations: summitward-research/vtsax-fzrox-fskax.
- Head-to-heads: FSKAX vs FZROX, FZROX vs VTSAX, VTSAX vs FSKAX, FZROX vs VTI, and VTI vs VTSAX. Guides: what Fidelity’s ZERO funds save, and what you give up, when switching to a cheaper index fund pays, and what Morningstar’s purchase of CRSP changed for VTI.
Disclosure: the author owns VTI, the ETF share class of VTSAX, for U.S. total-market exposure. Educational content, not individualized advice.
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